Download Physics 100 prac exam2

Physics 100 prac exam2
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1.
Earth's gravity attracts a person with a force of 120 lbs. The force with which the Earth is attracted
towards the person is
A. zero.
B. small but not zero.
C. billions and billions of tons.
D. 120 lbs.
2.
A rock that weighs 100 lb on Earth is taken to the Moon. As strange as it may seem, it is just as difficult
to lift the 100 lb rock on the Moon as on the Earth. This is because
A. the mass of the rock is independent of gravity.
B. the weight of the rock is independent of gravity.
C. Nonsense! The rock is more easily lifted on the Moon.
3.
An object weighs 20 newtons on Earth. What is its approximate mass?
A. 2 kg.
B. 20 g.
C. 10 kg.
D. 196 kg.
E. 640 kg.
4.
An object undergoes uniform circular motion. Which pair of vectors is perpendicular?
A. Its centripetal acceleration and the centripetal force.
B. Its centripetal acceleration and velocity vectors.
C. All three vectors are mutually perpendicular: centripetal acceleration, centripetal force, and velocity.
5.
A banked curve in a roadway is designed for a speed of 35 mph. During an ice storm cars should be able
to safely negotiate this curve at 35 mph, because at this speed
A. the necessary centripetal force is supplied entirely by gravity.
B. (and at all speeds) the acceleration vector of the car points down, helping maintain stability.
C. the centrifugal force of the car exactly balances the centripetal force.
D. the necessary centripetal force is supplied entirely by the normal force from the road.
6.
The mass of an apple on the Earth is 0.2 kg. On the Moon, the mass of the same apple would be
A. zero.
B. greater than zero but less than 0.2 kg.
C. 0.2 kg.
D. greater than 0.2 kg.
7.
Two cars that have the same mass are moving around a circular track at the same constant speed. The
track is perfectly level. If car 1 is at the inner edge of the track and car 2 is at the outer edge, then
A. the frictional force on car 1 is less than the frictional force on car 2.
B. the frictional force on car 1 is greater than the frictional force on car 2.
C. the frictional forces on both cars are equal and greater than zero.
D. the frictional force on both cars is zero.
8.
A cyclist races around a circular track at the constant speed of 20 m/s. The radius of the track is 50 m.
The acceleration of the cyclist is
A. zero.
B. 8 m/s2, toward the center of the track.
C. 10 m/s2, downward.
D. 20 m/s2, in the direction of travel.
9.
A ball is whirled on the end of a string in a horizontal circle at constant speed. Suddenly, the string
breaks. Immediately after the string breaks, the ball will
A. have a horizontal velocity away from the center of the circle.
B. have a horizontal velocity that is tangential to the circle.
C. have a horizontal velocity toward the center of the circle.
D. have a horizontal velocity partly in away from the center of the circle and partly tangent to the circle.
E. have no horizontal velocity.
10. According to Newton's Law of Gravitation, if the distance between two bodies is doubled the attractive
force between them becomes
A. twice as large.
B. half as large.
C. four times as large.
D. one quarter as large.
E. unchanged.
11. If two bicyclists move around a circular track of radius 100 m, at the same speed, 10 m/s, but in opposite
directions, then
A. they have equal size accelerations, 1 m/s2.
B. they have opposite accelerations, +1 m/s2 and -1 m/s2.
C. one has centripetal acceleration of 1 m/s2 and the other has centrifugal acceleration of 1 m/s2.
D. they might have different accelerations, depending on whether they have identical mass or not.
12. If work was done on an object, the object must have
A. changed its position.
B. accelerated.
C. experienced a frictional force.
D. changed only its direction of motion.
13. A brick slides across a horizontal rough surface and eventually comes to a stop. What happened to the
kinetic energy of the brick?
A. Nothing; it is still in the brick but is now called potential energy.
B. It was converted to other energy forms, mostly heat.
C. It was converted to a potential energy of friction.
D. It was simply destroyed in the process of stopping.
14. Which of the following is possessed by a moving object, but not by a stationary object?
A. Energy.
B. Kinetic energy.
C. Mass.
D. Inertia.
15. A 20 N ball and a 40 N ball are dropped at the same time from a height of 10 meters. Air resistance is
negligible. Which of the following statements is accurate?
A. After 1 second has elapsed, both balls have the same kinetic energy, since they have the same
acceleration.
B. The heavy ball has a greater acceleration and falls faster.
C. The light ball has a greater speed, since it can accelerate faster than the heavy ball.
D. Both balls hit the ground at the same time but gravity does more work on the heavy ball than on the
light ball.
16. When work is done by a force on an object, then which of the following is true?
A. The speed of the object must change.
B. The work done is equal to the change of total energy of the object plus any energy appearing as heat,
light, or sound.
C. The object does an equal amount of work on the force.
D. The object must change height above the ground.
E. The force cannot take energy away from the object.
17. A mass hangs from a spring that is fixed to the ceiling. The mass is now pulled down and released so the
mass oscillates up and down. Which of the following statements is true?
A. The kinetic energy of the oscillating mass is a constant.
B. Adding mass to the spring will make it oscillate faster.
C. The restoring force of the spring is equal to the weight of the mass.
D. The gravitational force on the mass oscillates at the same frequency as the mass.
E. None of these is true.
18. Jim exerts a force of 500 N against a 100-kg desk that does not move. Virgil exerts a force of 400 N
against a 60-kg desk that moves 2 m in the direction of the push. Mik exerts a force of 200 N against a
50-kg desk that moves 4 m in the direction of the push. The most work is done by
A. Jim.
B. Virgil.
C. Mik.
D. Virgil and Mik, who do equal amounts of work.
19. Suppose you climb the stairs of a ten-story building, about 30 m high, and your mass is 70 kg. The
gravitational potential energy you gain is about
A. 40 Joule.
B. 21,000 Joule.
C. 40 calories.
D. 21,000 calories.
20. Virgil rides a skateboard (combined mass 100 kg) at 4 m/s, and Jill rides a bicycle (combined mass 64 kg)
at 5 m/s.
A. Virgil has the greater kinetic energy.
B. Virgil and Jill have equal kinetic energies.
C. Jill has the greater kinetic energy.
21. An object with a kinetic energy of 50 J is stopped in a distance of 0.01 m. The average force that stops the
object is
A. 0.5 N.
B. 50 N.
C. 500 N.
D. 5,000 N.
E. 50,000 N.
22. A box is moved 10 m across by a floor a force of 20 N acting along the direction of motion. The work
done by the force is
A. 2.0 J.
B. 20 J.
C. 30 J.
D. 100 J.
E. 200 J.
23. A box is moved 10 m across a smooth floor by a force making a downward angle with the floor, so that
there is effectively a 10 N force acting parallel to the floor in the direction of motion and a 5 N force
acting perpendicular to the floor. The work done is
A. 150 J.
B. 100 J.
C. 50 J.
D. 10 J.
E. 5.0 J.
24. A box is pushed across a rough horizontal floor by a force acting parallel to the floor in the direction of
motion. A force doing negative work on the body is
A. gravity.
B. friction.
C. the applied force.
D. the normal reaction force of the floor upward on the body.
E. a fictitious force.
25. The kinetic energy of a body is correctly given by which of the following expressions?
A. mv.
B. 2mv2.
C. mv2.
D. (½)mv2.
E. (½)mv.
26. When a baseball bat hits the ball, the impulse delivered to the ball is increased by
A. "follow through" on the swing.
B. rapidly stopping the bat after impact.
C. letting the bat recoil upon impact.
D. The impulse cannot be changed.
27. Suppose you are out on a frozen lake, where there is no friction. Which of the following would start you
moving towards the shore?
A. Shouting at someone on the shore.
B. Removing a shoe and throwing it towards the shore.
C. Removing a shoe and throwing it away from the shore.
D. None of these would work.
28. A gun is made of a super-low-weight but strong material. The bullet for the gun is more massive than the
gun itself. For such a gun
A. recoil problems would be lessened.
B. the gun, if unsupported, would have a recoil velocity higher than the bullet velocity.
C. conservation of momentum is not satisfied.
D. the bullet would go faster with less powder.
29. The purpose of an air bag in an auto is to
A. reduce your speed just before a collision.
B. decrease the force applied to you during a collision.
C. reduce the impulse on you during a collision.
D. make your momentum change occur over a shorter time during a collision.
30. The momentum of a truck is increased by a factor of 2; its weight does not change. Thus,
A. its acceleration is doubled.
B. its speed increased by a factor of 4.
C. its speed doubled.
D. its kinetic energy doubled.
31. A quantity which is conserved in the collision of a car and a truck is
A. kinetic energy.
B. nervous energy.
C. momentum of the car.
D. total momentum.
E. momentum of the truck.
32. An 80-kg football player travels to the left at 10 m/s and a 120-kg player on the opposite team travels to
the right at 4.0 m/s. The total momentum is
A. 240 kg m/s to the left.
B. 320 kg m/s to the right.
C. zero.
D. 320 kg m/s to the left.
E. 1280 kg m/s to the right.
33. A 25-kg child runs at 4.0 m/s and jumps onto a shopping cart and holds on for dear life. The cart has mass
15 kg. Assuming the child rides on the cart after the collision, the speed of the child and shopping cart
just after the child jumps on is
A. zero.
B. 2.0 m/s.
C. 3.0 m/s.
D. 2.5 m/s.
34. In a head-on automobile collision, a person's momentum could be reduced from 2000 kg m/s to zero in
just 0.1 s. If this occurs, the average force exerted to stop the person is
A. 200 N.
B. 2,000 N.
C. 20,000 N.
D. This can't be answered without knowing the person's mass.
35. A child runs at 4.0 m/s and jumps onto a sled, initially at rest. If the child's mass is 36 kg, and if the child
and sled slide off together at 3.0 m/s after the collision, the sled's mass is
A. 12 kg.
B. 27 kg.
C. 36 kg.
D. 48 kg.
36. A fire fighting vehicle of mass 12,000 kg is at rest but free to roll with no resistance. If you push it
forward with a force of 500 N, the momentum at the end of 10 s of pushing will be
A. zero.
B. 5000 kg m/s.
C. 0.416 m/s.
D. 20,000 kg N/s.
37. The average force required to accelerate a 0.20-kg ball from rest to 30 m/s in 0.001 s is
A. 0.006 N
B. 6,000 N.
C. 30,000 N.
D. 150,000 N.
38. A 2 kg block, initially moving due east at 6 m/s, is acted upon by an impulse having magnitude 4 Ns and
direction due west. The final velocity of the block is
A. 8 m/s west.
B. 4 m/s west.
C. 4 m/s east.
D. 8 m/s east.
39. During a collision, which of these is an indication that the total kinetic energy has changed?
A. Heat is generated.
B. Deformation occurs.
C. Sound is produced.
D. Heat is generated, deformation occurs, and sound is produced.
E. None of these are correct.
40. A bullet of mass 0.010 kg and speed of 100 m/s is brought to rest in a wooden block after penetrating a
distance of 0.10 m. This process takes 0.02 second. The magnitude of the impulse delivered to the bullet
by the block during this time is
A. 0.50 Ns.
B. 1.0 Ns.
C. 2.0 Ns.
D. .98 N.
E. zero.
Physics 100 prac exam2 Key
1.
Earth's gravity attracts a person with a force of 120 lbs. The force with which the Earth is attracted
towards the person is
A. zero.
B. small but not zero.
C. billions and billions of tons.
D. 120 lbs.
2.
A rock that weighs 100 lb on Earth is taken to the Moon. As strange as it may seem, it is just as
difficult to lift the 100 lb rock on the Moon as on the Earth. This is because
A. the mass of the rock is independent of gravity.
B. the weight of the rock is independent of gravity.
C. Nonsense! The rock is more easily lifted on the Moon.
3.
An object weighs 20 newtons on Earth. What is its approximate mass?
A. 2 kg.
B. 20 g.
C. 10 kg.
D. 196 kg.
E. 640 kg.
4.
An object undergoes uniform circular motion. Which pair of vectors is perpendicular?
A. Its centripetal acceleration and the centripetal force.
B. Its centripetal acceleration and velocity vectors.
C. All three vectors are mutually perpendicular: centripetal acceleration, centripetal force, and
velocity.
5.
A banked curve in a roadway is designed for a speed of 35 mph. During an ice storm cars should be
able to safely negotiate this curve at 35 mph, because at this speed
A. the necessary centripetal force is supplied entirely by gravity.
B. (and at all speeds) the acceleration vector of the car points down, helping maintain stability.
C. the centrifugal force of the car exactly balances the centripetal force.
D. the necessary centripetal force is supplied entirely by the normal force from the road.
6.
The mass of an apple on the Earth is 0.2 kg. On the Moon, the mass of the same apple would be
A. zero.
B. greater than zero but less than 0.2 kg.
C. 0.2 kg.
D. greater than 0.2 kg.
7.
Two cars that have the same mass are moving around a circular track at the same constant speed. The
track is perfectly level. If car 1 is at the inner edge of the track and car 2 is at the outer edge, then
A. the frictional force on car 1 is less than the frictional force on car 2.
B. the frictional force on car 1 is greater than the frictional force on car 2.
C. the frictional forces on both cars are equal and greater than zero.
D. the frictional force on both cars is zero.
Griffith - Chapter 05 #1
Griffith - Chapter 05 #4
Griffith - Chapter 05 #6
Griffith - Chapter 05 #7
Griffith - Chapter 05 #9
Griffith - Chapter 05 #10
Griffith - Chapter 05 #13
8.
A cyclist races around a circular track at the constant speed of 20 m/s. The radius of the track is 50 m.
The acceleration of the cyclist is
A. zero.
B. 8 m/s2, toward the center of the track.
C. 10 m/s2, downward.
D. 20 m/s2, in the direction of travel.
9.
A ball is whirled on the end of a string in a horizontal circle at constant speed. Suddenly, the string
breaks. Immediately after the string breaks, the ball will
A. have a horizontal velocity away from the center of the circle.
B. have a horizontal velocity that is tangential to the circle.
C. have a horizontal velocity toward the center of the circle.
D. have a horizontal velocity partly in away from the center of the circle and partly tangent to the
circle.
E. have no horizontal velocity.
10.
According to Newton's Law of Gravitation, if the distance between two bodies is doubled the
attractive force between them becomes
A. twice as large.
B. half as large.
C. four times as large.
D. one quarter as large.
E. unchanged.
11.
If two bicyclists move around a circular track of radius 100 m, at the same speed, 10 m/s, but in
opposite directions, then
A. they have equal size accelerations, 1 m/s2.
B. they have opposite accelerations, +1 m/s2 and -1 m/s2.
C. one has centripetal acceleration of 1 m/s2 and the other has centrifugal acceleration of 1 m/s2.
D. they might have different accelerations, depending on whether they have identical mass or not.
12.
If work was done on an object, the object must have
A. changed its position.
B. accelerated.
C. experienced a frictional force.
D. changed only its direction of motion.
13.
A brick slides across a horizontal rough surface and eventually comes to a stop. What happened to the
kinetic energy of the brick?
A. Nothing; it is still in the brick but is now called potential energy.
B. It was converted to other energy forms, mostly heat.
C. It was converted to a potential energy of friction.
D. It was simply destroyed in the process of stopping.
14.
Which of the following is possessed by a moving object, but not by a stationary object?
A. Energy.
B. Kinetic energy.
C. Mass.
D. Inertia.
Griffith - Chapter 05 #14
Griffith - Chapter 05 #19
Griffith - Chapter 05 #24
Griffith - Chapter 05 #42
Griffith - Chapter 06 #2
Griffith - Chapter 06 #3
Griffith - Chapter 06 #4
15.
A 20 N ball and a 40 N ball are dropped at the same time from a height of 10 meters. Air resistance is
negligible. Which of the following statements is accurate?
A. After 1 second has elapsed, both balls have the same kinetic energy, since they have the same
acceleration.
B. The heavy ball has a greater acceleration and falls faster.
C. The light ball has a greater speed, since it can accelerate faster than the heavy ball.
D. Both balls hit the ground at the same time but gravity does more work on the heavy ball than on the
light ball.
16.
When work is done by a force on an object, then which of the following is true?
A. The speed of the object must change.
B. The work done is equal to the change of total energy of the object plus any energy appearing as
heat, light, or sound.
C. The object does an equal amount of work on the force.
D. The object must change height above the ground.
E. The force cannot take energy away from the object.
17.
A mass hangs from a spring that is fixed to the ceiling. The mass is now pulled down and released so
the mass oscillates up and down. Which of the following statements is true?
A. The kinetic energy of the oscillating mass is a constant.
B. Adding mass to the spring will make it oscillate faster.
C. The restoring force of the spring is equal to the weight of the mass.
D. The gravitational force on the mass oscillates at the same frequency as the mass.
E. None of these is true.
18.
Jim exerts a force of 500 N against a 100-kg desk that does not move. Virgil exerts a force of 400 N
against a 60-kg desk that moves 2 m in the direction of the push. Mik exerts a force of 200 N against a
50-kg desk that moves 4 m in the direction of the push. The most work is done by
A. Jim.
B. Virgil.
C. Mik.
D. Virgil and Mik, who do equal amounts of work.
19.
Suppose you climb the stairs of a ten-story building, about 30 m high, and your mass is 70 kg. The
gravitational potential energy you gain is about
A. 40 Joule.
B. 21,000 Joule.
C. 40 calories.
D. 21,000 calories.
20.
Virgil rides a skateboard (combined mass 100 kg) at 4 m/s, and Jill rides a bicycle (combined mass 64
kg) at 5 m/s.
A. Virgil has the greater kinetic energy.
B. Virgil and Jill have equal kinetic energies.
C. Jill has the greater kinetic energy.
21.
An object with a kinetic energy of 50 J is stopped in a distance of 0.01 m. The average force that stops
the object is
A. 0.5 N.
B. 50 N.
C. 500 N.
D. 5,000 N.
E. 50,000 N.
Griffith - Chapter 06 #7
Griffith - Chapter 06 #8
Griffith - Chapter 06 #12
Griffith - Chapter 06 #13
Griffith - Chapter 06 #14
Griffith - Chapter 06 #15
Griffith - Chapter 06 #16
22.
A box is moved 10 m across by a floor a force of 20 N acting along the direction of motion. The work
done by the force is
A. 2.0 J.
B. 20 J.
C. 30 J.
D. 100 J.
E. 200 J.
23.
A box is moved 10 m across a smooth floor by a force making a downward angle with the floor, so
that there is effectively a 10 N force acting parallel to the floor in the direction of motion and a 5 N
force acting perpendicular to the floor. The work done is
A. 150 J.
B. 100 J.
C. 50 J.
D. 10 J.
E. 5.0 J.
24.
A box is pushed across a rough horizontal floor by a force acting parallel to the floor in the direction
of motion. A force doing negative work on the body is
A. gravity.
B. friction.
C. the applied force.
D. the normal reaction force of the floor upward on the body.
E. a fictitious force.
25.
The kinetic energy of a body is correctly given by which of the following expressions?
A. mv.
B. 2mv2.
C. mv2.
D. (½)mv2.
E. (½)mv.
26.
When a baseball bat hits the ball, the impulse delivered to the ball is increased by
A. "follow through" on the swing.
B. rapidly stopping the bat after impact.
C. letting the bat recoil upon impact.
D. The impulse cannot be changed.
27.
Suppose you are out on a frozen lake, where there is no friction. Which of the following would start
you moving towards the shore?
A. Shouting at someone on the shore.
B. Removing a shoe and throwing it towards the shore.
C. Removing a shoe and throwing it away from the shore.
D. None of these would work.
28.
A gun is made of a super-low-weight but strong material. The bullet for the gun is more massive than
the gun itself. For such a gun
A. recoil problems would be lessened.
B. the gun, if unsupported, would have a recoil velocity higher than the bullet velocity.
C. conservation of momentum is not satisfied.
D. the bullet would go faster with less powder.
Griffith - Chapter 06 #21
Griffith - Chapter 06 #22
Griffith - Chapter 06 #23
Griffith - Chapter 06 #25
Griffith - Chapter 07 #1
Griffith - Chapter 07 #3
Griffith - Chapter 07 #4
29.
The purpose of an air bag in an auto is to
A. reduce your speed just before a collision.
B. decrease the force applied to you during a collision.
C. reduce the impulse on you during a collision.
D. make your momentum change occur over a shorter time during a collision.
30.
The momentum of a truck is increased by a factor of 2; its weight does not change. Thus,
A. its acceleration is doubled.
B. its speed increased by a factor of 4.
C. its speed doubled.
D. its kinetic energy doubled.
31.
A quantity which is conserved in the collision of a car and a truck is
A. kinetic energy.
B. nervous energy.
C. momentum of the car.
D. total momentum.
E. momentum of the truck.
32.
An 80-kg football player travels to the left at 10 m/s and a 120-kg player on the opposite team travels
to the right at 4.0 m/s. The total momentum is
A. 240 kg m/s to the left.
B. 320 kg m/s to the right.
C. zero.
D. 320 kg m/s to the left.
E. 1280 kg m/s to the right.
33.
A 25-kg child runs at 4.0 m/s and jumps onto a shopping cart and holds on for dear life. The cart
has mass 15 kg. Assuming the child rides on the cart after the collision, the speed of the child and
shopping cart just after the child jumps on is
A. zero.
B. 2.0 m/s.
C. 3.0 m/s.
D. 2.5 m/s.
34.
In a head-on automobile collision, a person's momentum could be reduced from 2000 kg m/s to zero
in just 0.1 s. If this occurs, the average force exerted to stop the person is
A. 200 N.
B. 2,000 N.
C. 20,000 N.
D. This can't be answered without knowing the person's mass.
35.
A child runs at 4.0 m/s and jumps onto a sled, initially at rest. If the child's mass is 36 kg, and if the
child and sled slide off together at 3.0 m/s after the collision, the sled's mass is
A. 12 kg.
B. 27 kg.
C. 36 kg.
D. 48 kg.
Griffith - Chapter 07 #5
Griffith - Chapter 07 #8
Griffith - Chapter 07 #9
Griffith - Chapter 07 #14
Griffith - Chapter 07 #17
Griffith - Chapter 07 #18
Griffith - Chapter 07 #19
36.
A fire fighting vehicle of mass 12,000 kg is at rest but free to roll with no resistance. If you push it
forward with a force of 500 N, the momentum at the end of 10 s of pushing will be
A. zero.
B. 5000 kg m/s.
C. 0.416 m/s.
D. 20,000 kg N/s.
37.
The average force required to accelerate a 0.20-kg ball from rest to 30 m/s in 0.001 s is
A. 0.006 N
B. 6,000 N.
C. 30,000 N.
D. 150,000 N.
38.
A 2 kg block, initially moving due east at 6 m/s, is acted upon by an impulse having magnitude 4 Ns
and direction due west. The final velocity of the block is
A. 8 m/s west.
B. 4 m/s west.
C. 4 m/s east.
D. 8 m/s east.
39.
During a collision, which of these is an indication that the total kinetic energy has changed?
A. Heat is generated.
B. Deformation occurs.
C. Sound is produced.
D. Heat is generated, deformation occurs, and sound is produced.
E. None of these are correct.
40.
A bullet of mass 0.010 kg and speed of 100 m/s is brought to rest in a wooden block after penetrating
a distance of 0.10 m. This process takes 0.02 second. The magnitude of the impulse delivered to the
bullet by the block during this time is
A. 0.50 Ns.
B. 1.0 Ns.
C. 2.0 Ns.
D. .98 N.
E. zero.
Griffith - Chapter 07 #20
Griffith - Chapter 07 #21
Griffith - Chapter 07 #27
Griffith - Chapter 07 #32
Griffith - Chapter 07 #38
Physics 100 prac exam2 Summary
Category
Griffith - Chapter 05
Griffith - Chapter 06
Griffith - Chapter 07
# of Question
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