PY 131 Exam 1 review

A 10 Newton falling object encounters 10 Newtons of air resistance. The net force on the object is Select one: a. 10 Newtons. b. 6 Newtons. c. 0 Newtons. d. 4 Newtons.

c

A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 3 seconds. The speed of the car just before the brakes were applied was a) 30 m/s. b) 1.2 m/s. c) 15 m/s. d) none of these e) 45 m/s.

c

A TV set is pushed a distance of 2 m with a force of 20 N. How much work is done on the set? a) 800J b) 10J c) 40J d) 2J e) 20J

c

A car with a mass of 1647 kg moves at 18 m/s. What braking force is needed to bring the car to a halt in 10s?

-2964.6 N

A 9 kg fish swimming 10 m/s swallows an absent minded 1 kg fish swimming toward it at a velocity that bring both fish to a halt immediately after lunch. What is the velocity of the smaller fish before lunch?

-90 m/s

A railroad engine weighs 7 times as much as a freight car. If the engine coasts at 2 km/h into a freight car that is initially at rest, how fast do the two coast after they couple together?

1.75 km/h

A 5-kg shark swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 5 m/s. The speed of the shark after this meal is a) 0 m/s. b) 1/2 m/s. c) 1/5 m/s. d) 1/6 m/s. e) 5/3 m/s.

a

A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is a) 300 N upward. b) 500 N upward. c) 500 N downward. d) 300 N downward. e) 800 N downward.

a

A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has a) 16 times the KE. b) 12 times the KE. c) 8 times the KE. d) 4 times the KE.

a

A clerk can lift containers a vertical distance of 1 meter or can roll them up a 2 meter-long ramp to the same elevation. With the ramp, the applied force required is about a) half as much. b) four times as much. c) the same. d) twice as much.

a

A large truck and a small car traveling at the same speed have a head on collision. The vehicle that undergoes the greatest change in velocity will be the Select one: a. small car. b. same for both. c. large truck.

a

A sheet of paper can be withdrawn from under a cup of water without spilling if the paper is yanked out quickly. This best demonstrates that Select one: a. the cup of water has inertia. b. the cup of water has no acceleration. c. none of these. d. gravity tends to hold the cup of water secure.

a

If a rocket initially at rest accelerates at a rate of 50 m/s2 for one minute, its speed will be a) 3000 m/s. b) 50 m/s. c) 500 m/s. d) 3600 m/s.

a

If no external forces are acting on a moving object it will Select one: a. continue moving at the same velocity. b. continue moving at the same speed. c. move slower and slower until it finally stops.

a

If we removed the air resistance, objects would fall with constant Select one: a. acceleration. b. distances each consecutive second. c. velocity. d. speed.

a

If you were to put very large diameter tires on your truck, your speedometer will measure a speed that is Select one: a. lower than it is actually. b. the same as before. c. higher than it is actually.

a

It takes 6 seconds for a stone to fall to the bottom of a canyon. How deep is the canyon? Select one: a. about 180m. b. about 60m. c. about 120m. d. about 200m.

a

Put a pipe over the end of a wrench when trying to turn a stubborn nut on a bolt, to effectively make the wrench handle twice as long, you'll multiply the torque by a) two. b) eight. c) four.

a

Thanks to new NCAA regulations, all of the players on our Men's basketball team will be given a 2015 Bentley. During a test drive one of the players splattered a bug on his windshield while traveling 55 mph. Which experienced the greater force? a) The same for both. b) The car. c) more information needed d) The bug.

a

The famous Leaning Tower of Pisa doesn't topple over because its center of gravity is a) above a place of support. b) in the same place as its center of mass. c) stabilized by its structure. d) relatively low for such a tall building. e) displaced from its center.

a

The gain in speed each second for a freely-falling object is about a) 10 m/s. b) 20 m/s. c) depends on the initial speed d) 5 m/s. e) 0.

a

The last instant just before a free falling elevator car crashes, a passenger jumps out the door and falls only two feet to the ground. The passenger is Select one: a. probably hurt or killed. b. intelligent to think so fast. c. unharmed. d. lucky to have studied physics.

a

The two measurements necessary for calculating average speed are Select one: a. distance and time. b. acceleration and time. c. velocity and time. d. distance and acceleration. e. velocity and distance.

a

When a rocket ship accelerating in outer space runs out of fuel it Select one: a. no longer accelerates. b. accelerates for a short time, slows down and eventually stops. c. accelerates for a short time, then slows down to a constant velocity.

a

Which has zero acceleration? An object Select one: a. All of these. b. moving at a constant velocity. c. in mechanical equilibrium. d. at rest.

a

While riding on a Ferris wheel at the state fair, you are seated 10 m from the axis. If you make a complete rotation every minute, what is your linear speed? (hint: you need to find the circumference) Select one: a. 62.8 m/min. b. 31.4 m/min. c. 100 m/min.

a

A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy of Select one: a. less than 40 J. b. 40 J. c. more than 40 J.

b

A bullet is dropped into a gorge from a high cliff. At the same time, another bullet is fired from a gun, straight down towards the base of the gorge. Neglecting air resistance, the acceleration just before striking the water Select one: a. depends on how hight they started. b. is the same for each bullet. c. is greater for the fired bullet. d. is greater for the dropped bullet.

b

A car moving at 50 km/hr skids 20 m with locked brakes. How far will the car skid with locked brakes if it were traveling at 150 km/hr? a) 60m b) 180m c) 20m d) 120m e) 90m

b

A heavy object and a light object are dropped at the same time from rest in a vacuum. The heavier object reaches the ground Select one: a. after the lighter object b. at the same time as the lighter object. c. before the lighter object.

b

A man leans over the edge of a cliff and throws a rock upward at 5 m/s. How far below the level from which it was thrown is the rock 2 seconds later? a) 20m b) 10m c) 15m d) 5m

b

A person is attracted toward the center of the Earth by a 500 N gravitational force. The Earth is attracted toward the person with a force of Select one: a. 0 N. b. 500 N. c. 1000 N. d. 250 N.

b

A ring and a disk, initially at rest, roll down a hill together. The one to reach the bottom first a) Both reach the bottom at the same time. b) is the disk. c) is the ring. d) depends on the masses. e) depends on the relative rotational inertias.

b

A train boxcar is moving at a constant velocity. Inside the storage compartment, a rock is dropped from teh midpoint of the ceiling and strikes the floor below. The rock hits the floor Select one: a. none of these. b. exactly below the midpoint of the ceiling. c. ahead of the midpoint of the ceiling. d. behind the midpoint of the ceiling. e. more information is needed to solve this problem.

b

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint the ceiling and strikes the floor below. The rock hits the floor a) behind the midpoint of the ceiling. b) exactly below the midpoint of the ceiling. c) ahead of the midpoint of the ceiling. d) none of these e) More information is needed to solve this problem.

b

An object is propelled along a straight line path by a force. If the net force were doubled, the objects acceleration would be Select one: a. the same. b. twice as much. c. half as much. d. four times as much.

b

An object lifted 10 meters gains 200 J of potential energy. If the same object is lifted 20 meters, its potential energy gain is Select one: a. four times as much. b. twice as much. c. more than four times as much. d. half as much. e. the same.

b

If a large truck loaded with bricks has a head on collision with a small car, which will experience the greater acceleration? Select one: a. The large truck. b. The small car. c. both will experience the same acceleration.

b

If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting point is about Select one: a. 1s. b. 2s. c. 20s. d. 10s. e. Not enough information given.

b

If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about a) 10 seconds. b) 2 seconds. c) 1 second. d) not enough information to estimate e) 20 seconds.

b

If a rocket accelerates from rest at a rate of 50 m/s2 for 10s, the distance it will cover during this time is Select one: a. 5000m. b. 2500m. c. 500m. d. 250m.

b

The attraction of a person's body toward the Earth is called weight. The reaction to this force is Select one: a. the Earth's surface pushing against the person's body. b. the person's body pulling on the Earth. c. the person's body pushing against the Earth's surface.

b

The force of friction on a sliding object is 10 Newtons. The applied force needed to maintain a constant velocity is Select one: a. less than 10 Newtons. b. 10 Newtons. c. more than 10 Newtons.

b

To turn a really tight screw, it would be easier fi you were to choose a screwdriver that has a Select one: a. long handle. b. wide (or fat) handle. c. narrow (or skinny) handle.

b

When a falling object has reached its terminal velocity, its acceleration is a) constant. b) zero. c) g.

b

When bullets are fired from an airplane in the forward direction, the momentum of the airplane will be Select one: a. increased. b. decreased. c. unchanged.

b

A bullet is dropped from the top of the Empire State Building while another bullet is fired downward from the same location. Neglecting air resistance, the acceleration of a) the fired bullet is greater. b) the dropped bullet is greater. c) each bullet is 9.8 meters per second per second.

c

A coin and a ring, each with the same mass, roll down an incline starting at the same time. Which one will reach the bottom first? Select one: a. It's a tie. b. The ring. c. The coin.

c

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is a) equal to its weight divided by its mass. b) equal to its weight. c) zero. d) equal to the product of its mass times its weight.

c

A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is a) 800 N. b) none of these c) 400 N. d) 1600 N. e) 200 N.

c

A pizza chef tosses a spinning disk of uncooked pizza dough into the air. The disk's diameter increases during the flight, while its rotational speed Select one: a. remains constant. b. increases. c. decreases.

c

A sandbag is motionless in outer space. A second sandbag with 3 times the mass moving at 12 m/s collides with it. They stick together and move at a speed of a) 3 m/s. b) 8 m/s. c) none of these d) 6 m/s. e) 4 m/s.

c

An object lifted 10 meters gains 200 J of potential energy. If the same object is lifted 20 meters, its potential energy gain is a) more than four times as much. b) four times as much. c) twice as much. d) half as much. e) the same.

c

Hang from a pair of gym rings and the upward support forces from the rings will always Select one: a. each be half your weight. b. each be equal to your weight. c. add up to equal your weight.

c

If a baseball being thrown goes from zero to 60 m/s in 0.2 seconds, what is the average acceleration? Select one: a. 30 m/s2 b. 3 m/s2 c. 300 m/s2 d. 3000 m/s2

c

If a large truck loaded with bricks has a head on collision with a small car, which will experience the greater change in momentum? Select one: a. The large truck. b. The small car. c. Both will experience the same change in momentum.

c

If a large truck loaded with bricks has a head on collision with a small car, which will experience the greater force of impact? Select one: a. The large truck. b. The small car c. Force is the same for both.

c

If a large truck loaded with bricks has a head on collision with a small car, which will experience the greater impulse? Select one: a. The large truck. b. The small car. c. Both will experience the same impulse.

c

If you push an object twice as far while applying the same force, you do Select one: a. the same amount of work on both. b. half as much work. c. twice as much work. d. four times as much work.

c

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? a) more than 200 m b) about 120 m c) about 180 m d) about 60 m

c

Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has a) decreased time of impact. b) decreased impulse. c) increased time of impact. d) increased momentum.

c

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction from the first force. The particle with both forces acting on it a) decelerates gradually to a halt. b) none of these c) continues at the speed it had when it encountered the second force. d) theoretically tends to accelerate toward the speed of light. e) is brought to a rapid halt.

c

When a twirling ice skater brings her arms inward, her rotational speed a) decreases. b) remains the same. c) increases.

c

When doing flips off of a diving board, you'll more easily rotate when your body is Select one: a. straight as a board. b. in any orientation. c. balled up.

c

Which moves faster in m/s on a merry-go-round: a horse on the inside or a horse on the outside near the outer rail? a) inside horse b) Both move at the same speed in m/s. c) outside horse

c

An object falls freely from rest on a planet where the acceleration due to gravity is 20 m/s2. After 5 seconds, the object will have a speed of Select one: a. 5 m/s. b. 10 m/s. c. 20 m/s. d. 50 m/s. e. 100 m/s.

e

A ball rolling down an incline has its maximum kinetic energy at a) three-quarters of the way down. b) halfway down. c) the top. d) the bottom.

d

A car has a mass of 1000kg and accelerates at 2 m/s2. What is the magnitude of the net force exerted on the car? Select one: a. 1000 Newtons b. 1500 Newtons c. 500 Newtons d. 2000 Newtons

d

A girl pulls on a 10-kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon's acceleration in meters per second per second? a) 300 b) 0.3 c) 10 d) 3.0 e) 30

d

After the best physics test ever you decided to drive around the 440 beltline to enjoy your greatness. You make one rotation around the 30 mile beltline in 30 minutes. What is your average velocity? a) 30 miles/hour. b) 60 miles/hour. c) 30 m/s. d) 0 miles/hour. e) None of these choices are correct.

d

Compared to the mass of a certain object on Earth, the mass of the same object on the moon is a) one sixth as much. b) six times as much. c) zero. d) the same.

d

If an object of constant mass experiences a constant net force, it will have a constant a) velocity. b) speed. c) position. d) acceleration. e) more than one of these

d

It takes 40 J to push a large box 4 m across a floor. Assuming the push is in the same direction as the move, what is the magnitude of the force on the box? Select one: a. 4 N. b. 40 N. c. 160 N. d. 10 N.

d

Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's acceleration in meters per second per second? a) 10 b) 40 c) 2.8 d) 4.0 e) 0.25

d

Which of the following is absolute and can never be questioned? a) Theory b) Hypothesis c) Keith d) nonsense, they all can be proven wrong. e) Law

d

A 2-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground? a) 6J b) 32J c) none of these d) 8J e) 80J

e

A girl pulls on a 10 kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon's acceleration in m/s2? Select one: a. 0.3 m/s2 b. 300 m/s2 c. 10 m/s2 d. 30 m/s2 e. 3.0 m/s2

e

If a freely falling object were to somehow equipped with a speedometer, its speed reading would increase each second by Select one: a. 15 m/s. b. depends on the initial speed. c. a variable amount d. 5 m/s. e. 10 m/s.

e