# Physics I Midterm

1) x = -1.5

For which of the values below is x > x^3?

1) 3.16 x 10^7, 86 400

One year is about ____ seconds while one day is exactly ____ seconds.

1) 3 800

Calculate (0.82 + 0.042) x (4.4 x 10^3), keeping only significant figures.

1) 0.13 cubic feet

A cereal box has the dimensions of 0.19 m x 0.28 m x 0.070 m. If there are 3.28 feet per meter, then what is the volume of the box in cubic feet?

1) 5 730 guppies

On planet Q the standard unit of volume is called the guppy. Space travelers from Earth have determined that one liter = 38.2 guppies. How many guppies are in 150 liters?

1) 0.003 6 in

The information on a one-gallon paint can is that the coverage, when properly applied, is 450 ft2. One gallon is 231 in^3. What is the average thickness of the paint in such an application?

1) 2.68 x 10-8 m

Modern electroplaters can cover a surface area of 60.0 m2 with one troy ounce of gold (volume = 1.611 cm3). What is the thickness of the electroplated gold?

1) two up quarks and one down quark

The proton contains which of the following combination of quarks?

1) 27 500 furlongs/fortnight

A furlong is a distance of 220 yards. A fortnight is a time period of two weeks. A race horse is running at a speed of 5.00 yards per second. What is his speed in furlongs per fortnight?

1) 290

Which one of the choices below represents the preferred practice regarding significant figures when multiplying the following: 10.5 x 8.8 x 3.14?

1) v/x

Which expression is dimensionally consistent with an expression that would yield a value for time-1?(v is velocity, x is distance, and t is time)

1) 86.8 m

A train slowly climbs a 500-m mountain track which is at an angle of 10.0° with respect to the horizontal. How much altitude does it gain?

2) 1

If j = 90o – q, what is the value of sin^2 j + sin^2 q?

2) L2, L3

Areas always have dimensions ____ while volumes always have dimensions ____.

2) 384 000 km

When NASA was communicating with astronauts on the moon, the time from sending on the Earth to receiving on the moon was 1.28 s. Find the distance from Earth to the moon. (The speed of radio waves is 3.00 x 10^8 m/s.)

2) if x is halved, y is multiplied by eight

Note the expression: y = A/x^3. Which statement is most consistent with this expression?

2) 17.3 in

Each edge of a cube has a length of 25.4 cm. What is the length of a diagonal of the cube going through the center of the cube?

2) 10^4 ft^3

An apartment has 1100 ft^2 of floor space. What is the approximate volume of the apartment?

2) 64 hours

Water flows into a swimming pool at the rate of 8.0 gal/min. The pool is 16 ft wide, 32 ft long and 8.0 ft deep. How long does it take to fill? (1 U.S. gallon = 231 cubic inches)

2) 10 m

If point A is located at coordinates (5, 3) and point B is located at coordinates (-3, 9), what is the distance from A to B if the units of the coordinated system are meters?

2) 24 cm

A triangle has sides of length 7.0 cm and 25 cm. If the triangle is a right triangle, which of the following could be the length of the third side?

2) 23°

A right triangle has sides 5.0 m, 12 m, and 13 m. The smallest angle of this triangle is nearest:

2) 1.5 million tons

Assume everyone in the United States consumes one soft drink in an aluminum can every two days. If there are 270 million Americans, how many tons of aluminum need to be recycled each year if each can weighs 1/16 pound and one ton = 2000 pounds?

2) 5.5 feet

On planet Z, the standard unit of length is the foose. Ann the Astronaut is 5.90 feet tall on earth. She lands on planet Z and is measured to be 94 foosi tall. Her partner Rachael is 88 foosi tall. How tall is Rachael on Earth?

3) 8

Doubling the radius of a sphere results in increasing its volume by a factor of

3) 10^-12, 10^-9, and 10^9

The prefixes which are abbreviated p, n, and G represent which of the following?

3) 1.2 x 10^57 atoms

The mass of the sun is 2.0 x 10^30 kg, and the mass of a hydrogen atom is 1.67 x 10^-27 kg. If we assume that the sun is mostly composed of hydrogen, how many atoms are there in the sun?

3) m/s

The speed of a boat is often given in knots. If a speed of 5 knots were expressed in the SI system of units, the units would be:

3) in 1932

When was the existence of the neutron confirmed?

3) length and time

In mechanics, physicists use three basic quantities to derive additional quantities. Mass is one of the three quantities. What are the other two?

3) 4.0

A circle has an area of 2.0 m2. A second circle has double the radius of the first. The area of the second circle is ____ times that of the first.

3) 2 x 10^22 m

The distance to the Andromeda Galaxy is estimated at about 2 x 10^6 light years. A light year is the distance traveled by light in one year; if the speed of light is 3 x 10^8 m/s, about how far is it from our galaxy to Andromeda? (1 year = 3.15 x 10^7 s)

3) L/T3, L/T4

Suppose an equation relating position, x, to time, t, is given by x = b t^3 + c t^4, where b and c are constants. The dimensions of b and c are respectively:

3) 10^9

The ratio M/m of the prefixes M and m has what value?

3) v = a/t

If a is acceleration, v is velocity, x is position, and t is time, then which equation is not dimensionally correct?

3) 2

Multiplying a 2 significant figure number by a 3 significant figure number and then dividing the product by a six significant figure number yields a number with how many significant figures?

3) time

If the displacement of an object, x, is related to velocity, v, according to the relation x = Av, the constant, A, has the dimension of which of the following?

3) 10^4

A physics class in a large lecture hall has 150 students. The total mass of the students is about ____ kg.

4) 4

The length and width of a standard sheet of paper is measured, and then the area is found by calculation to be 93.50 in2. The number of significant figures in the width measurement must be at least:

4) at

Which formula is dimensionally consistent with an expression yielding a value for velocity? (a is acceleration, x is distance, and t is time)

4) 95

Which one of the choices below represents the preferred practice regarding significant figures when adding the following: 12.4 + 11 + 67.37 + 4.201?

4) 45 000 cm^2

The basic function of an automobile’s carburetor is to atomize the gasoline and mix it with air to promote rapid combustion. Assume that 30 cm^3 of gasoline is atomized into N spherical droplets. Each droplet has a radius of 2.0 x 10^-5 m. Find the total surface area of these N spherical droplets.

4) protons and neutrons

The nuclei of atoms contain:

4) 9 ft^3/min

A cement truck can pour 20 cubic yards of cement per hour. Express this in ft^3/min.

4) if x doubles, then y quadruples

Note the expression: y = x^2. Which statement is most consistent with this expression?

4) (5, -2)

Which point is nearest the x axis?

4) 34 m

A high fountain of water is in the center of a circular pool of water. You walk the circumference of the pool and measure it to be 150 meters. You then stand at the edge of the pool and use a protractor to gauge the angle of elevation of the top of the fountain. It is 55°. How high is the fountain?

1) 4.00 s

A rock is thrown straight up with an initial velocity of 19.6 m/s. What time interval elapses between the rock’s being thrown and its return to the original launch point? (Acceleration due to gravity is 9.80 m/s^2.)

1) 3.47 m/s^2

A European sports car dealer claims that his car will accelerate at a constant rate from rest to 100 km/hr in 8.00 s. If so, what is the acceleration? (Hint: First convert speed to m/s.)

1) vector

Displacement is which of the following types of quantities?

1) It is positive.

In one-dimensional motion, the average speed of an object that moves from one place to another and then back to its original place has which of the following properties?

1) 12.6 s

A cheetah can run at approximately 100 km/hr and a gazelle at 80.0 km/hr. If both animals are running at full speed, with the gazelle 70.0 m ahead, how long before the cheetah catches its prey?

1) 150 m

An automobile driver puts on the brakes and decelerates from 30.0 m/s to zero in 10.0 s. What distance does the car travel?

1) 396 m/s

Mt. Everest is more than 8 000 m high. How fast would an object be moving if it could free fall to sea level after being released from an 8000-m elevation? (Ignore air resistance.)

1) 13 400 m/s^2

A 50-g ball traveling at 25.0 m/s is bounced off a brick wall and rebounds at 22.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 3.50 ms, what is the average acceleration of the ball during this time interval?

1) 914 m

A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 58.8 m/s in 6.00 seconds. She then pulls the parachute cord and after a 4.00-second constant deceleration, descends at 10.0 m/s for 60.0 seconds, reaching the ground. From what height did the parachutist jump?

1) 0.50 m/s

An object moves 20 m east in 30 s and then returns to its starting point taking an additional 50 s. If west is chosen as the positive direction, what is the average speed of the object?

1) 2.31 m/s^2

A Cessna aircraft has a lift-off speed of 120 km/hr. What minimum constant acceleration does this require if the aircraft is to be airborne after a take-off run of 240 m?

1) positive, positive.

If the displacement of an object is given in SI units by Dx = -3 t + 4 t^2, at t = 2 s its velocity and acceleration are, respectively:

1) 28 m/s

Gwen releases a rock at rest from the top of a 40-m tower. If g = 9.8 m/s2 and air resistance is negligible, what is the speed of the rock as it hits the ground?

1) temperature

Which of the following is not a vector quantity?

1) 40 m

A truck moves 70 m east, then moves 120 m west, and finally moves east again a distance of 90 m. If east is chosen as the positive direction, what is the truck’s resultant displacement?

1) 15 m/s

A rock, released at rest from the top of a tower, hits the ground after 1.5 s. What is the speed of the rock as it hits the ground? (g = 9.8 m/s2 and air resistance is negligible)

2) 0.46 m/s^2

A bird, accelerating from rest at a constant rate, experiences a displacement of 28 m in 11 s. What is its acceleration?

2) 1.8 x 10^2 m

A baseball is released at rest from the top of the Washington Monument. It hits the ground after falling for 6.0 s. What was the height from which the ball was dropped? (g = 9.8 m/s2 and assume air resistance is negligible)

2) 167 m

A cheetah can maintain its maximum speed of 100 km/hr for 30.0 seconds. What minimum distance must a gazelle running 80.0 km/hr be ahead of the cheetah to escape?

2) the rate of change of acceleration.

The slope of the acceleration vs. time curve represents:

2) the velocity of the ball is not changing.

A v vs. t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 5 s the acceleration of the ball is zero. We know that at t = 5 s,

2) 2.5 m/s

A bird, accelerating from rest at a constant rate, experiences a displacement of 28 m in 11 s. What is the average velocity?

2) average velocity

On a position versus time graph, the slope of the straight line joining two points on the plotted curve that are separated in time by the interval Dt, is which of the following quantities?

2) 4 s

Maria throws two stones from the top edge of a building with a speed of 20 m/s. She throws one straight down and the other straight up. The first one hits the street in a time t1. How much later is it before the second stone hits?

2) 61.5 m/s

A railroad train travels forward along a straight track at 80.0 m/s for 1 000 m and then travels at 50.0 m/s for the next 1 000 m. What is the average velocity?

2) 89 m/s

A drag racer starts from rest and accelerates at 10 m/s^2 for the entire distance of 400 m (1/4 mile). What is the velocity of the race car at the end of the run?

2) 9.80 m/s.

A ball is thrown vertically upwards at 19.6 m/s. For its complete trip (up and back down to the starting position), its average speed is:

2) wf – wi

A change in a physical quantity w having initial value wi and final value wf is given by which of the following?

2) at the top of its trajectory

A baseball catcher throws a ball vertically upward and catches it in the same spot when it returns to his mitt. At what point in the ball’s path does it experience zero velocity and non-zero acceleration at the same time?

2) 49 m

A rock is thrown straight down with an initial velocity of 14.5 m/s from a cliff. What is the rock’s displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s^2.)

2) 18.6 miles/s

The distance of the Earth from the sun is 93 000 000 miles. If there are 3.15 ´ 107 s in one year, find the speed of the Earth in its orbit about the sun.

2) Both objects hit the ground together

Two objects of different mass are released simultaneously from the top of a 20-m tower and fall to the ground. If air resistance is negligible, which statement best applies?

2) 28 m/s

John throws a rock down with speed 14 m/s from the top of a 30-m tower. If g = 9.8 m/s2 and air resistance is negligible, what is the rock’s speed just as it hits the ground?

2) the ball has stopped.

An x vs. t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 5 s the velocity of the ball is zero. We can be positive that at t = 5 s,

2) at the top

Jeff throws a ball straight up. For which situation is the vertical velocity zero?

3) 61 m

A water rocket, launched from the ground, rises vertically with acceleration of 30 m/s^2 for

1.0 s when it runs out of “fuel.” Disregarding air resistance, how high will the rocket rise?

1.0 s when it runs out of “fuel.” Disregarding air resistance, how high will the rocket rise?

3) the acceleration of the car

A strobe photograph shows equally spaced images of a car moving along a straight road. If the time intervals between images is constant, which of the following cannot be positive?

3) 10 m/s^2

A vehicle designed to operate on a drag strip accelerates from zero to 30 m/s while undergoing a straight line path displacement of 45 m. What is the vehicle’s acceleration if its value may be assumed to be constant?

3) 66 m

A cart is given an initial velocity of 5.0 m/s and experiences a constant acceleration of 2.0 m/s2. What is the magnitude of the cart’s displacement during the first 6.0 s of its motion?

3) speed

Changing the positive direction in a reference frame to the opposite direction does not change the sign of which of the following quantities?

3) half-way through the time interval.

In the case of constant acceleration, the average velocity equals the instantaneous velocity:

3) 5.1 m/s

A bird, accelerating from rest at a constant rate, experiences a displacement of 28 m in 11 s. What is the final velocity after 11 s?

3) 111 m

A European sports car dealer claims that his product will accelerate at a constant rate from rest to a speed of 100 km/hr in 8.00 s. What distance will the sports car travel during the 8 s acceleration period? (Hint: First convert speed to m/s.)

3) 44 m

Omar throws a rock down with speed 12 m/s from the top of a tower. The rock hits the ground after 2.0 s. What is the height of the tower? (air resistance is negligible)

3) 0 (no sign)

An object moves 20 m east in 30 s and then returns to its starting point taking an additional 50 s. If west is chosen as the positive direction, what is the sign associated with the average velocity of the object?

3) the average acceleration of the car

A strobe photograph of a car moving along a straight road shows the interval between each successive image to be diminishing. If the direction of motion of the car is taken as positive, which of the following are negative?

4) 5.6 m/s

A basketball player can jump 1.6 m off the hardwood floor. With what upward velocity did he leave the floor?

4) 12 m

Norma releases a bowling ball from rest; it rolls down a ramp with constant acceleration. After half a second it has traveled 0.75 m. How far has it traveled after two seconds?

4) 17.4 m/s

A European sports car dealer claims that his product will accelerate at a constant rate from rest to a speed of 100 km/hr in 8.00 s. What is the speed after the first 5.00 s of acceleration? (Hint: First convert the speed to m/s.)

4) Its velocity is never equal to its acceleration.

An object is dropped from a height. Once it is moving, which of the following statements is true, at least at one point?

4) 20 cm.

Human reaction time is usually about 0.20 s. If your lab partner holds a ruler between your finger and thumb and releases it without warning, how far can you expect the ruler to fall before you catch it? The nearest value is:

4) 30.6 m

A rock is thrown straight up with an initial velocity of 24.5 m/s. What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s2.)

4) 1.78 s

At the top of a cliff 100 m high, Raoul throws a rock upward with velocity 15.0 m/s. How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?

4) 240 m

When a drag strip vehicle reaches a velocity of 60 m/s, it begins a negative acceleration by releasing a drag chute and applying its brakes. While reducing its velocity back to zero, its acceleration along a straight line path is a constant -7.5 m/s2. What displacement does it undergo during this deceleration period?

4) rate of change of velocity

The value of an object’s acceleration may be characterized in equivalent words by which of the following?

4) 17 m/s

A ball is pushed with an initial velocity of 4.0 m/s. The ball rolls down a hill with a constant acceleration of 1.6 m/s2. The ball reaches the bottom of the hill in 8.0 s. What is the ball’s velocity at the bottom of the hill?

4) It can be positive, negative, or zero.

In one-dimensional motion where the direction is indicated by a plus or minus sign, the average velocity of an object has which of the following properties?

1) 58 m

A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 12 m/s. A stop watch measures the stone’s trajectory time from top of cliff to bottom to be 5.6 s. How far out from the cliff’s edge does the stone travel horizontally? (g = 9.8 m/s2 and air resistance is negligible)

1) 607 mph, 5.67° N of E

A jet airliner moving at 500 mph due east moves into a region where the wind is blowing at 120 mph in a direction 30.0° north of east. What is the new velocity and direction of the aircraft?

1) 76.4 m

John throws a baseball from the outfield from shoulder height, at an initial velocity of 29.4 m/s at an initial angle of 30.0° with respect to the horizontal. The ball is in its trajectory for a total interval of 3.00 s before the third baseman catches it at an equal shoulder-height level. (Assume air resistance negligible.) What is the ball’s horizontal displacement?

1) 1.8 minutes

The highest mountain on Mars is Olympus Mons, rising 22 000 meters above the Martian surface. If we were to throw an object horizontally off the mountain top, how long would it take to reach the surface? (Ignore atmospheric drag forces and use gMars = 3.72 m/s2.)

1) 11.0 m

A baseball thrown from the outfield is released from shoulder height at an initial velocity of 29.4 m/s at an initial angle of 30.0° with respect to the horizontal. What is the maximum vertical displacement that the ball reaches during its trajectory?

1) 38 m

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 35 m building. If g = 9.8 m/s2 and air resistance is negligible, what is the magnitude of the horizontal displacement of the rock?

1) another velocity.

When we subtract a velocity vector from another velocity vector, the result is:

1) dividing by cosine

In a 2-dimensional Cartesian system, the x-component of a vector is known, and the angle between vector and x-axis is known. Which operation is used to calculate the magnitude of the vector? (taken with respect to the x-component)

1) 5.7° W of N

A plane is moving due north, directly towards its destination. Its airspeed is 200 mph. A constant breeze is blowing from west to east at 20 mph. In which direction is the plane pointed?

1) 59° N of E

Arvin the Ant travels 30 cm eastward, then 25 cm northward, and finally 15 cm westward. What is Arvin’s direction of displacement with respect to his original position?

1) 198 mph

A plane is moving due north, directly towards its destination. Its airspeed is 200 mph. A constant breeze is blowing from west to east at 30 mph. At what rate is the plane moving north?

1) 226 m

Wiley Coyote has missed the elusive road runner once again. This time, he leaves the edge of the cliff at 50.0 m/s horizontal velocity. If the canyon is 100 m deep, how far from his starting point at the edge of the cliff does the coyote land?

1) velocity

Which of the following is an example of a vector quantity?

1) 43 yards

A quarterback takes the ball from the line of scrimmage, runs backward for 10 yards, then sideways parallel to the line of scrimmage for 15 yards. He then throws a 50-yard forward pass straight downfield perpendicular to the line of scrimmage. The receiver is tackled immediately. How far is the football displaced from its original position?

1) 2 m.

The first displacement is 6 m and the second displacement is 3 m. They cannot add together to give a total displacement of:

2) more than one hour

A plane is moving due north, directly towards its destination. Its airspeed is 200 mph. A constant breeze is blowing from west to east at 40 mph. How long will it take for the plane to travel 200 miles north?

2) cosine

In a 2-dimensional Cartesian coordinate system the x-component of a given vector is equal to that vector’s magnitude multiplied by which trigonometric function, with respect to the angle between vector and x-axis?

2) 61.4 newtons 21.8°

The following force vectors act on an object: i) 50.0 newtons at 45.0° north of east and ii) 25.0 newtons at 30.0° south of east. Which of the following represents the magnitude of the resultant and its angle relative to the easterly direction?

2) 0.84 s

A track star in the broad jump goes into the jump at 12 m/s and launches himself at 20° above the horizontal. How long is he in the air before returning to Earth? (g = 9.8 m/s2)

2) cosine

In a 2-dimensional Cartesian coordinate system the y-component of a given vector is equal to that vector’s magnitude multiplied by which trigonometric function, with respect to the angle between vector and y-axis?

2) 7.8 m/s

A bridge that was 5.0 m long has been washed out by the rain several days ago. How fast must a car be going to successfully jump the stream? Although the road is level on both sides of the bridge, the road on the far side is 2.0 m lower than the road on this side.

2) 2 km/h

A boat travels upstream and after one hour has gone 10 km. The boat next travels downstream and after one hour has gone 14 km. If the boat’s speed relative to the water is constant, what is the speed of the current in the river?

2) the upstream trip

A boat moves through the water in a river at a speed of 8 m/s relative to the water. The boat makes a trip downstream and then makes a return trip upstream to the original starting place. Which trip takes longer?

2) 120 m, 188 m

A jogger runs halfway around a circular path with a radius of 60 m. What, respectively, are the magnitude of the displacement and the distance jogged?

2) 2nd

An object, initially moving in the negative x-direction, is subjected to a change in velocity in the positive y-direction. If the resulting velocity vector is drawn from the origin, into which quadrant does this vector point?

2) 11 m/s

An object moves at a constant velocity of 11 m/s to the southwest for an interval of 20 s. Halfway through this interval, what is the magnitude of its instantaneous velocity?

2) vector

Which type of quantity is characterized by both magnitude and direction?

2) 9.0 m/s

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 35 m building. If g = 9.8 m/s2 and air resistance is negligible, then what is the magnitude of the horizontal component of velocity as the rock strikes the ground?

2) occurs one-half of the way around the track

A runner circles a track of radius 100 m one time in 100 s at a constant rate. The greatest change in his velocity from his starting velocity:

2) 200

A student adds two vectors with magnitudes of 200 and 40. Which one of the following is the only possible choice for the magnitude of the resultant?

2) 0.072 m

A ball is rolled horizontally off a table with an initial speed of 0.24 m/s. A stop watch measures the ball’s trajectory time from table to the floor to be 0.30 s. How far away from the table does the ball land? (g = 9.8 m/s2 and air resistance is negligible)

3) 18.7 m

A fireman, 50.0 m away from a burning building, directs a stream of water from a fire hose at an angle of 30.0° above the horizontal. If the initial speed of the stream is 40.0 m/s, at what height will the stream of water strike the building?

3) 60 m/s

A helicopter is traveling at 40 m/s at a constant altitude of 100 m over a level field. If a wheel falls off the helicopter, with what speed will it hit the ground? (g = 9.8 m/s2 and air resistance negligible)

3) 0.25 m/s^2, south

A runner circles a track of radius 100 m in 100 s moving at a constant rate. If the runner was initially moving north, what has been the runner’s average acceleration when halfway around the track?

3) another displacement.

When we add a displacement vector to another displacement vector, the result is:

3) 180°

When three vectors are added graphically and form a closed triangle, the largest enclosed angle between any two of the vectors cannot be greater than:

3) at the top of the trajectory

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at an equal shoulder level) by the catcher. At what point is the ball’s speed at a minimum? (air resistance is negligible)

3) 357 mph

Plane A is flying at 400 mph in the northeast direction relative to the earth. Plane B is flying at 500 mph in the north direction relative to the earth. What is the speed of Plane B as observed from Plane A?

3) 95 N, 55 N

Jack pulls a sled across a level field by exerting a force of 110 N at an angle of 30° with the ground. What are the parallel and perpendicular components, respectively, of this force with respect to the ground?

3) 24.1 N

Five boys are pushing on a snowball, and each is pushing with a force of 10.0 N. However, each boy is pushing in a different direction. They are pushing north, northeast, east, southeast, and south. (Each boy is pushing at an angle of 45.0° relative to his neighbor.) What is the magnitude of the total force on the ball?

3) 37.5° N of W

Plane A is flying at 400 mph in the northeast direction relative to the earth. Plane B is flying at 500 mph in the north direction relative to the earth. What is the direction of motion of Plane B as observed from Plane A?

3) 120 m

A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 12 m/s. A stop watch measures the stone’s trajectory time from top of cliff to bottom to be 5.6 s. What is the height of the cliff? (g = 9.8 m/s2 and air resistance is negligible)

3) 30 m/s

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 35 m building. If g = 9.8 m/s2 and air resistance is negligible, then what is the speed of the rock as it hits the ground?

3) 208 s

A boat moves at 10.0 m/s relative to the water. If the boat is in a river where the current is 2.00 m/s, how long does it take the boat to make a complete round trip of 1 000 m upstream followed by a 1 000-m trip downstream?

3) 13.4 m

A baseball leaves the bat with a speed of 44.0 m/s and an angle of 30.0° above the horizontal. A 5.0-m-high fence is located at a horizontal distance of 132 m from the point where the ball is struck. Assuming the ball leaves the bat 1.0 m above ground level, by how much does the ball clear the fence?

3) at the top of the trajectory

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at shoulder level) by the catcher. At what point does the magnitude of the vertical component of velocity have its minimum value? (air resistance is negligible)

3) 7.00 s, 143 m/s

Superguy is flying at treetop level near Paris when he sees the Eiffel Tower elevator start to fall (the cable snapped). His x-ray vision tells him Lois LaTour is inside. If Superguy is 1.00 km away from the tower, and the elevator falls from a height of 240 m, how long does Superguy have to save Lois, and what must be his average speed?

4) 29 cm

Arvin the Ant is on a picnic table. He travels 30 cm eastward, then 25 cm northward, and finally 15 cm westward. What is the magnitude of Arvin’s net displacement?

4) 29 m/s

A stone is thrown with an initial speed of 15 m/s at an angle of 53° above the horizontal from the top of a 35 m building. If g = 9.8 m/s2 and air resistance is negligible, then what is the magnitude of the vertical velocity component of the rock as it hits the ground?

4) 62 units 54° north of west

Find the resultant of the following two vectors: i) 50 units due east and ii) 100 units 30° north of west.

4) 0.44 m

A ball is rolled horizontally off a table with an initial speed of 0.24 m/s. A stopwatch measures the ball’s trajectory time from table to the floor to be 0.30 s. What is the height of the table? (g = 9.8 m/s2 and air resistance is negligible)

4) acceleration is constant during entire trajectory

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at shoulder level) by the catcher. At what point is the magnitude of the acceleration at a minimum? (air resistance is negligible)

4) 90 m

A river flows due east at 3.0 m/s. A boat crosses the 300-m-wide river by maintaining a constant velocity of 10 m/s due north relative to the water. If no correction is made for the current, how far downstream does the boat move by the time it reaches the far shore?

4) All of the above statements are false

Two projectiles are launched at 100 m/s, the angle of elevation for the first being 30° and for the second 60°. Which of the following statements is false?

4) 71°

I walk six miles in a straight line in a direction north of east, and I end up two miles east and several miles north. How many degrees north of east have I walked?

4) 92 m

A string attached to an airborne kite is maintained at an angle of 40° with the horizontal. If a total of 120 m of string is reeled in while bringing the kite back to the ground, what is the horizontal displacement of the kite in the process? (Assume the kite string doesn’t sag.)

4) 700 m/s

A rifle is aimed horizontally toward the center of a target 100 m away. If the bullet strikes 10 cm below the center, what was the velocity of the bullet? (Ignore air friction.)

4) zero

A baseball thrown from the outfield is released from shoulder height at an initial velocity of 29.4 m/s at an initial angle of 30.0° with respect to the horizontal. If it is in its trajectory for a total of 3.00 s before being caught by the third baseman at an equal shoulder-height level, what is the ball’s net vertical displacement during its 3-s trajectory?

4) north of west

A car is initially moving at 20 m/s east and a little while later it is moving at 10 m/s north. Which of the following best describes the orientation of the average acceleration during this time interval?

4) 8.6 blocks

A taxicab moves five blocks due north, five blocks due east, and another two blocks due north. Assume all blocks are of equal size. What is the magnitude of the taxi’s displacement, start to finish?

4) 86 m

A ball is launched from ground level at 30 m/s at an angle of 35° above the horizontal. How far does it go before it is at ground level again?

1) 2.0 m/s2

An airplane of mass 1.2 ´ 104 kg tows a glider of mass 0.6 ´ 104 kg. The airplane propellers provide a net forward thrust of 3.6 ´ 104 N. What is the glider’s acceleration?

1) 6.5 m/s2 downward.

As a 3.0-kg bucket is being lowered into a 10-m-deep well, starting from the top, the tension in the rope is 9.8 N. The acceleration of the bucket will be:

1) 14 N

Two blocks of masses 20 kg and 8.0 kg are connected together by a light string and rest on a frictionless level surface. Attached to the 8-kg mass is a second light string, which a person uses to pull both blocks horizontally. If the two-block system accelerates at 0.5 m/s2, what is the tension in the second string attached to the 8-kg mass?

1) 12 N

Three identical 6.0-kg cubes are placed on a horizontal frictionless surface in contact with one another. The cubes are lined up from left to right and a force is applied to the left side of the left cube causing all three cubes to accelerate to the right at 2.0 m/s2. What is the magnitude of the force exerted on the right cube by the middle cube in this case?

1) 1.2 m/s2

Two ropes are attached to a 40-kg object. The first rope applies a force of 25 N and the second, 40 N. If the two ropes are perpendicular to each other, what is the resultant acceleration of the object?

1) 94 N

A sled weighs 100 N. It is held in place on a frictionless 20° slope by a rope attached to a stake at the top; the rope is parallel to the slope. What is the normal force of the slope acting on the sled?

1) 41.4 N

A 10.0-kg mass is placed on a 25.0o incline and friction keeps it from sliding. The coefficient of static friction in this case is 0.580, and the coefficient of sliding friction is 0.520. What is the frictional force in this situation?

1) 2.2 m/s2

A 2 000-kg sailboat experiences an eastward force of 3 000 N by the ocean tide and a wind force against its sails with magnitude of 6 000 N directed toward the northwest (45° N of W). What is the magnitude of the resultant acceleration?

1) 28.7 m

Hector drives a pickup truck horizontally at 15.0 m/s. He is transporting a crate of delicate lead crystal. If the coefficient of static friction between the crate and the truck bed is 0.400, what is the minimum stopping distance for the truck so the crate will not slide?

1) 1 440 N

A 500-N tightrope walker stands at the center of the rope such that each half of the rope makes an angle of 10.0° with the horizontal. What is the tension in the rope?

1) 15 500 N

A 70.0-kg man jumps 1.00 m down onto a concrete walkway. His downward motion stops in 0.0200 seconds. If he forgets to bend his knees, what force is transmitted to his leg bones?

1) 450 N

A baseball batter hits an incoming 40-m/s fastball. The ball leaves the bat at 50 m/s after a ball-on-bat contact time of 0.030 s. What is the force exerted on the 0.15-kg baseball?

1) 924 N

A trapeze artist, with swing, weighs 800 N; he is being held to one side by his partner so that the swing ropes make an angle of 30.0° with the vertical. In such a condition of static equilibrium what is the tension in the rope?

1) 1.8 m/s2

A horizontal force of 750 N is needed to overcome the force of static friction between a level floor and a 250-kg crate. What is the acceleration of the crate if the 750-N force is maintained after the crate begins to move and the coefficient of kinetic friction is 0.12?

1) 71 kg

An astronaut applies a force of 500 N to an asteroid, and it accelerates at 7.00 m/s2. What is the asteroid’s mass?

1) the net force acting on the object is zero.

If we know an object is moving at constant velocity, we may assume:

1) bigger than his weight.

As a basketball player starts to jump for a rebound, he begins to move upward faster and faster until he leaves the floor. During this time that he is in contact with the floor, the force of the floor on his shoes is:

1) 12 N

Three identical 6.0-kg cubes are placed on a horizontal frictionless surface in contact with one another. The cubes are lined up from left to right and a 36-N force is applied to the left side of the left cube causing all three cubes to accelerate to the right. If the cubes are each subject to a frictional force of 6.0 N, what is the magnitude of the force exerted on the right cube by the middle cube in this case?

1) 0.35

Dana uses a rope to pull a box that weighs 300 N across a level surface with constant velocity. The rope makes an angle of 30° above the horizontal and the tension in the rope is 100 N. What is the coefficient of friction?

2) 0.22

A 150-N sled is pulled up a 28° slope at a constant speed by a force of 100 N. What is the coefficient of kinetic friction between sled and slope?

2) 90 m

An automobile of mass 2 000 kg moving at 30 m/s is braked suddenly with a constant braking force of 10 000 N. How far does the car travel before stopping?

2) 0.267

A worker pulls a 200-N packing crate at constant velocity across a rough floor by exerting a force F = 55.0 N at an angle of 35.0° above the horizontal. What is the coefficient of kinetic friction of the floor?

2) 6.5 m/s2

A 10-kg mass and a 2.0-kg mass are connected by a light string over a massless, frictionless pulley. If g = 9.8 m/s2, what is the acceleration of the system when released?

2) 6 640 N

A 5 000-N weight is held suspended in equilibrium by two cables. Cable 1 applies a horizontal force to the right of the object and has a tension, T1. Cable 2 applies a force upward and to the left at an angle of 37.0° to the negative x axis and has a tension, T2. What is the tension, T1?

2) 24 N

Three identical 6.0-kg cubes are placed on a horizontal frictionless surface in contact with one another. The cubes are lined up from left to right and a 36-N force is applied to the left side of the left cube causing all three cubes to accelerate to the right. If the cubes are each subject to a frictional force of 6.0 N, what is the magnitude of the force exerted on the middle cube by the left cube in this case?

2) in constant velocity

What condition must apply to a system’s state of motion for it to be regarded as an inertial frame of reference?

2) mA > mB

Two objects, A and B, are placed on an inclined plane that can be rotated to different angles of elevation. A starts to slide at twice the angle of elevation that B starts sliding. The respective coefficients for static friction for A and B are mA and mB. Choose the last answer that is correct.

2) -0.477 m/s2

A 10.0-kg mass is placed on a 25.0o incline and friction keeps it from sliding. The coefficient of static friction in this case is 0.580 and the coefficient of sliding friction is 0.520. The mass is given a shove causing it to slide down the incline. Taking down the incline as positive, what is the acceleration of the mass while it is sliding?

2) 8°

A 500-N tightrope walker stands at the center of the rope. If the rope can withstand a tension of 1 800 N without breaking, what is the minimum angle the rope can make with the horizontal?

2) is less than the launching speed.

A block is launched up an incline plane. After going up the plane, it slides back down to its starting position. The coefficient of friction between the block and the plane is 0.3. The speed of the block when it reaches the starting position on the trip down:

2) 21°

A 250-kg crate is placed on an adjustable inclined plane. If the crate slides down the incline with an acceleration of 0.70 m/s2 when the incline angle is 25°, then what should the incline angle be for the crate to slide down the plane at constant speed? (g = 9.8 m/s2)

2) 4.2 m/s2

A rock is rolled in the sand. It starts at 5.0 m/s, moves in a straight line for a distance of 3.0 m, and then stops. What is the magnitude of the average acceleration?

2) the force of the stone on the glass = the force of the glass on the stone.

A thrown stone hits a window, but doesn’t break it. Instead it reverses direction and ends up on the ground below the window. In this case, we know:

2) 2.5 m/s2 due north

The accelerating force of the wind on a small 200-kg sailboat is 707 N northeast. If the drag of the keel is 500 N acting west, what is the acceleration of the boat?

2) 5.0 N

There are six books in a stack, each with a weight of 5.0 N. The coefficient of friction between all the books is 0.20 as is the coefficient between the table and the bottom book. What horizontal push must I just exceed on the next to bottom book to start sliding the top five books off the bottom one?

2) 8 000 N

Find the tension in an elevator cable if the 1 000-kg elevator is descending with an acceleration of 1.8 m/s2, downward.

2) 145 m

An Olympic skier moving at 20.0 m/s down a 30.0° slope encounters a region of wet snow, of coefficient of friction µk = 0.740. How far down the slope does she go before stopping?

2) 24 N

Three identical 6.0-kg cubes are placed on a horizontal frictionless surface in contact with one another. The cubes are lined up from left to right and a force is applied to the left side of the left cube causing all three cubes to accelerate to the right at 2.0 m/s2. What is the magnitude of the force exerted on the middle cube by the left cube in this case?

2) 0.31 N

A cart of weight 20 N is accelerated across a level surface at 0.15 m/s2. What net force acts on the wagon? (g = 9.8 m/s2)

2) µ = 0.033

A hockey puck moving at 7.0 m/s coasts to a halt in 75 m on a smooth ice surface. What is the coefficient of friction between the ice and the puck?

2) 0.27

A 100-kg box is placed on a ramp. As one end of the ramp is raised, the box begins to move downward just as the angle of inclination reaches 15°. What is the coefficient of static friction between box and ramp?

2) the one above the horizontal

A box is to be moved across a level surface. A force of magnitude 200 N may be applied at an angle of 30° below the horizontal to push the box or at an angle of 30° above the horizontal to pull the box, either application sufficient to overcome friction and move the box. Which application will cause the box to have the greater acceleration?

2) 350 N

A shot-putter moves his arm and the 7.0-kg shot through a distance of 1.0 m, giving the shot a velocity of 10 m/s from rest. Find the average force exerted on the shot during this time.

3) 4 900 N

A 20-kg traffic light hangs midway on a cable between two poles 40 meters apart. If the sag in the cable is 0.40 meters, what is the tension in each side of the cable?

3) 37°

The coefficient of static friction between the tires of a car and the street is µs = 0.77. Of the following, what is the steepest inclination angle of a street on which a car can be parked (with wheels locked) without slipping?

3) 600 N

A barefoot field-goal kicker imparts a speed of 30 m/s to a football at rest. If the football has a mass of 0.50 kg and time of contact with the football is 0.025 s, what is the force exerted on the foot?

3) 22.0 N

Two forces act on a 6.00-kg object. One of the forces is 10.0 N. If the object accelerates at 2.00 m/s2, what is the greatest possible magnitude of the other force?

3) 46.2 N

A 10.0-kg mass is placed on a 25.0o incline and friction keeps it from sliding. The coefficient of static friction in this case is 0.580, and the coefficient of sliding friction is 0.520. The mass is given a shove causing it to slide down the incline. What is the frictional force while the mass is sliding?

3) 50 N.

A 100-N block, on a 30° incline, is being held motionless by friction. The coefficient of static friction between the block and the plane is 0.60. The force due to friction is:

3) The natural condition for a moving object is to remain in motion.

Which of the following expresses a principle, which was initially stated by Galileo and was later incorporated into Newton’s laws of motion?

3) 10 N

Two blocks of masses 20 kg and 8 kg are connected together by a light string and rest on a frictionless level surface. Attached to the 8-kg mass is another light string, which a person uses to pull both blocks horizontally. If the two-block system accelerates at 0.5 m/s2 what is the tension in the connecting string between the blocks?

3) 0.39

A 300-kg crate is placed on an adjustable inclined plane. As one end of the incline is raised, the crate begins to move downward. If the crate slides down the plane with an acceleration of 0.70 m/s2 when the incline angle is 25°, what is the coefficient of kinetic friction between ramp and crate? (g = 9.8 m/s2)

3) is less than the time for the trip down.

A block is launched up an incline plane. After going up the plane, it slides back down to its starting position. The coefficient of friction between the block and the plane is 0.3. The time for the trip up the plane:

3) 24 N

Rita accelerates a 0.40-kg ball from rest to 9.0 m/s during the 0.15 s in which her foot is in contact with the ball. What average force does she apply to the ball during the kick?

3) being accelerated.

If we know that a nonzero net force is acting on an object, which of the following must we assume regarding the object’s condition? The object is:

3) third

The statement by Newton that “for every action there is an opposite but equal reaction” is regarded as which of his laws of motion?

3) 48 N

A man pulls a sled at a constant velocity across a horizontal snow surface. If a force of 80 N is being applied to the sled rope at an angle of 53° to the ground, what is the force of friction between sled and snow?

3) 37 m

Doug hits a hockey puck, giving it an initial velocity of 6.0 m/s. If the coefficient of kinetic friction between ice and puck is 0.050, how far will the puck slide before stopping?

3) 12 N

Two blocks, joined by a string, have masses of 6.0 and 9.0 kg. They rest on a frictionless horizontal surface. A 2nd string, attached only to the 9-kg block, has horizontal force = 30 N applied to it. Both blocks accelerate. Find the tension in the string between the blocks.

3) 19.8 N

A block of mass 5.00 kg rests on a horizontal surface where the coefficient of kinetic friction between the two is 0.200. A string attached to the block is pulled horizontally, resulting in a 2.00-m/s2 acceleration by the block. Find the tension in the string. (g = 9.80 m/s2)

3) 8 310 N

A 5 000-N weight is suspended in equilibrium by two cables. Cable 1 applies a horizontal force to the right of the object and has a tension, T1. Cable 2 applies a force upward and to the left at an angle of 37.0° to the negative x axis and has a tension, T2. Find T2.

3) weight.

In the terminology a 500-N block, the 500-N refers to the block’s:

3) the normal force of the road times the coefficient of static friction

As a car goes up a hill, there is a force of friction between the road and the tires rolling on the road. The maximum force of friction is equal to:

3) 89 m/s

The coefficient of friction between a racecar’s wheels and the track is 1.0. The car starts from rest and accelerates at a constant rate for 400 m. Find the maximum speed at the end of the race.

3) Carlos will continue down at a constant velocity

It is late and Carlos is sliding down a rope from his third floor window to meet his friend Juan. As he slides down the rope faster and faster, he becomes frightened and grabs harder on the rope, increasing the tension in the rope. As soon as the upward tension in the rope becomes equal to his weight:

3) less than the normal force of the road times the coefficient of static friction

As a car skids with its wheels locked trying to stop on a road covered with ice and snow, the force of friction between the icy road and the tires will usually be:

4) 0.31

A horizontal force of 750 N is needed to overcome the force of static friction between a level floor and a 250-kg crate. If g = 9.8 m/s2, what is the coefficient of static friction?

4) 4 500 N

A karate master strikes a board with an initial velocity of 10.0 m/s, decreasing to 1.0 m/s as his hand passes through the board. If the time of contact with the board is 0.002 0 s, and the mass of the coordinated hand and arm is 1.0 kg, what is the force exerted on the board?

4) 50 lb

The acceleration due to gravity on the Moon’s surface is one-sixth that on Earth. An astronaut’s life support backpack weighs 300 lbs on Earth. What does it weigh on the Moon?

4) 2.67 m/s2

Jamal pulls a 150-N sled up a 28.0° slope at constant speed by a force of 100 N. Near the top of the hill he releases the sled. With what acceleration does the sled go down the hill?

4) less than the weight of the box.

As I slide a box at constant speed up a frictionless slope, pulling parallel to the slope, the tension in the rope will be:

4) 250 N

A girl is using a rope to pull a box that weighs 300 N across a level surface with constant velocity. The rope makes an angle of 30° above the horizontal, and the tension in the rope is 100 N. What is the normal force of the floor on the box?

4) all of the above

Which of the following is an example of the type of force that acts at a distance?

4) zero.

As a car moves forward on a level road at constant velocity, the net force acting on the tires is:

4) greater than 1.00.

The maximum possible value for the coefficient of static friction is:

4) 462 N

A trapeze artist, with swing, weighs 800 N; he is momentarily held to one side by his partner so that the swing ropes make an angle of 30.0° with the vertical. In such a condition of static equilibrium, what is the horizontal force being applied by the partner?

4) 0.47

A 200-N crate rests on an ramp; the maximum angle just before it slips is 25° with the horizontal. What is the coefficient of static friction between crate and ramp surfaces?

4) 120 N

The acceleration due to gravity on the Moon’s surface is one-sixth that on Earth. What net force would be required to accelerate a 20-kg object at 6.0 m/s2 on the moon?

4) 38 N

A 9.0-kg hanging weight is connected by a string over a pulley to a 5.0-kg block sliding on a flat table. If the coefficient of sliding friction is 0.20, find the tension in the string.

4) 0.71 m/s2

A 7.0-kg bowling ball experiences a net force of 5.0 N. What will be its acceleration?

4) 74° N of W

A 2 000-kg sailboat experiences an eastward force of 3 000 N by the ocean tide and a wind force against its sails with magnitude of 6 000 N directed toward the northwest (45° N of W). What is the direction of the resultant acceleration?

4) 4.3 m/s

A boxcar of mass 200 tons at rest becomes uncoupled on a 2.5° grade. If the track is considered to be frictionless, what speed does the boxcar have after 10 seconds?

4) 26 100 N

An elevator weighing 20 000 N is supported by a steel cable. What is the tension in the cable when the elevator is being accelerated upward at a rate of 3.00 m/s2? (g = 9.80 m/s2)

4) 34 N

A sled weighs 100 N. It is held in place on a frictionless 20° slope by a rope attached to a stake at the top; the rope is parallel to the slope. Find the tension in the rope.

4) 37 N

A 15-kg block rests on a level frictionless surface and is attached by a light string to a 5.0-kg hanging mass where the string passes over a massless frictionless pulley. If g = 9.8 m/s2, what is the tension in the connecting string?

1) 2.5 km/s

The escape speed from the surface of the Earth is 11.2 km/s. Estimate the escape speed for a spacecraft from the surface of the Moon. The Moon has a mass 1/81 that of Earth and a radius 0.25 that of Earth.

1) nothing

According to Kepler’s second law, Halley’s Comet circles the Sun in an elliptical path with the Sun at one focus of the ellipse. What is at the other focus of the ellipse?

1) upward.

Consider a point on a bicycle tire that is momentarily in contact with the ground as the bicycle rolls across the ground with constant speed. The direction for the acceleration for this point at that moment is:

1) 7.3 ´ 10-5 rad/s

What is the angular speed about the rotational axis of the Earth for a person standing on the surface?

1) 1.1 m/s2

A ventilation fan has blades 0.25 m long rotating at 20 rpm. What is the centripetal acceleration of a point on the outer tip of a blade?

1) nearest the Earth

An artificial Earth satellite in an elliptical orbit has its greatest centripetal acceleration when it is at what location?

1) 0.05 rad/s

A cylindrical space colony 8 km in diameter and 30 km long has been proposed as living quarters for future space explorers. Such a habitat would have cities, land and lakes on the inside surface and air and clouds in the center. All this would be held in place by the rotation of the cylinder about the long axis. How fast would such a cylinder have to rotate to produce a 1-g gravitational field at the walls of the cylinder?

1) 29.4 m/s2

If a planet has 3 times the radius of the Earth, but has the same density as the Earth, what is the gravitational acceleration at the surface of the planet? (g = 9.8 m/s2)

1) 7.9 N

A 0.30-kg rock is swung in a circular path and in a vertical plane on a 0.25-m-length string. At the top of the path, the angular speed is 12.0 rad/s. What is the tension in the string at that point?

1) nearest the Earth

At what location does an artificial Earth satellite in elliptical orbit have its greatest speed?

1) greatest centripetal acceleration.

Of the nine known planets in our solar system, the innermost is Mercury. When compared to the other planets in the system, Mercury has the:

1) is in the same direction.

A wheel is rotated about a horizontal axle at a constant angular speed. Next it is rotated in the opposite direction with the same angular speed. The acceleration at a point on the top of the wheel in the second case as compared to the acceleration in the first case:

1) 40.7 rev/s

What angular speed (in revolutions/second) is needed for a centrifuge to produce an acceleration of 1 000 g at a radius arm of 15.0 cm?

1) 4.48 rad

A Ferris wheel, rotating initially at an angular speed of 0.500 rad/s, accelerates over a 7.00-s interval at a rate of 0.040 0 rad/s2. What angular displacement does the Ferris wheel undergo in this 7-s interval?

1) 0.45 m/s2

A 0.15-m-radius grinding wheel starts at rest and develops an angular speed of 12.0 rad/s in 4.0 s. What is the average tangential acceleration of a point on the wheel’s edge?

1) 1.8 years

For any object orbiting the Sun, Kepler’s Law may be written T2 = kr3. If T is measured in years and r in units of the Earth’s distance from the Sun, then k = 1. What, therefore, is the time (in years) for Mars to orbit the Sun if its mean radius from the Sun is 1.5 times the Earth’s distance from the Sun?