Exam 2 - Conceptual

Question 1

9) A rubber ball and a lump of clay have equal mass. They are thrown with equal speed against a wall. The ball bounces back with nearly the same speed with which it hit. The clay sticks to the wall. Which one of these objects experiences the greater momentum change?

A) the ball
B) the clay
C) Both of them experience the same non-zero momentum change.
D) Both of them experience zero momentum change.

Answer 1

A) the ball

Question 2

10) Which of the following quantities are units of momentum? (There could be more than one correct choice.)

A) N ∙ m
B) kg ∙ s/m
C) kg ∙ m/s
D) N ∙ s
E) kg ∙ m2/s2

Answer 2

C) kg ∙ m/s
D) N ∙ s

Question 3

11) The momentum of an isolated system is conserved

A) only in inelastic collisions.
B) only in elastic collisions.
C) in both elastic and inelastic collisions.

Answer 3

C) in both elastic and inelastic collisions

Question 4

12) Two friends are standing on opposite ends of a canoe that is initially at rest with respect to a frictionless lake. The person in the front throws a very massive ball toward the back, and the person in the back catches it. After the ball is caught, the canoe is

A) moving backward.
B) stationary.
C) moving forward.

Answer 4

B) stationary.

Question 5

13) You are standing on a skateboard, initially at rest. A friend throws a very heavy ball towards you. You have two choices about what to do with the ball: either catch the ball or deflect it back toward your friend with the same speed as it was originally thrown. Which choice should you make in order to maximize your speed on the skateboard?

A) Catch the ball.
B) Deflect the ball back.
C) Your final speed on the skateboard will be the same regardless whether you catch the ball or deflect the ball.

Answer 5

B) Deflect the ball back.

Question 6

A small car meshes with a large truck in a head-on collision. Which of the following statements concerning the magnitude of the momentum change during the collision is correct?

A) The truck experiences the greater magnitude momentum change.
B) The small car experiences the greater magnitude momentum change.
C) The small car and the truck experience the same magnitude momentum change.
D) The magnitude of the momentum change experienced by each one is inversely proportional to its mass.
E) The magnitude of the momentum change experienced by each one is directly proportional to its mass.

Answer 6

C) The small car and the truck experience the same magnitude momentum change.

Question 7

15) A rocket explodes into two fragments, one 25 times heavier than the other. The magnitude of the momentum change of the lighter fragment is

A) 25 times as great as the momentum change of the heavier fragment.
B) The same as the momentum change of the heavier fragment.
C) 1/25 as great as the momentum change of the heavier fragment.
D) 5 times as great as the momentum change of the heavier fragment.
E) 1/4 as great as the momentum change of the heavier fragment.

Answer 7

B) The same as the momentum change of the heavier fragment.

Question 8

16) Which of the following quantities are units of impulse? (There could be more than one correct choice.)

A) N ∙ m
B) kg ∙ s/m
C) kg ∙ m/s
D) N ∙ s
E) kg ∙ m2/s2

Answer 8

C) kg ∙ m/s
D) N ∙ s

Question 9

17) In a collision between two unequal masses, which mass receives a greater magnitude impulse?

A) the larger mass
B) the smaller mass
C) They receive equal impulses.

Answer 9

C) They receive equal impulses.

Question 10

18) Identical forces act for the same length of time on two different objects. The magnitude of the change in momentum of the lighter object is

A) smaller than the magnitude of the change in momentum of the larger mass, but not zero.
B) larger than the magnitude of the change in momentum of the larger mass.
C) exactly equal to the magnitude of the change in momentum of the larger mass.
D) zero.
E) There is not enough information to answer the question.

Answer 10

C) exactly equal to the magnitude of the change in momentum of the larger mass.

Question 11

19) In an inelastic collision involving an isolated system, the final total momentum is

A) exactly the same as the initial momentum.
B) more than the initial momentum.
C) less than the initial momentum.

Answer 11

A) exactly the same as the initial momentum.

Question 12

20) A 5-kg ball collides inelastically head-on with a 10-kg ball, which is initially stationary. Which of the following statements is true? (There could be more than one correct choice.)

A) The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball.
B) The magnitude of the change of velocity the 5-kg ball experiences is less than that of the 10-kg ball.
C) The magnitude of the change of velocity the 5-kg ball experiences is equal to that of the 10-kg ball.
D) The magnitude of the change of the momentum of the 5-kg ball is equal to the magnitude of the change of momentum of the 10-kg ball.
E) Both balls lose all their momentum since the collision is inelastic.

Answer 12

A) The magnitude of the change of velocity the 5-kg ball experiences is greater than that of the 10-kg ball.

D) The magnitude of the change of the momentum of the 5-kg ball is equal to the magnitude of the change of momentum of the 10-kg ball.

Question 13

21) In a game of pool, the white cue ball hits the #5 ball and stops, while the #5 ball moves away with the same velocity as the cue ball had originally. Both balls have the same mass. This type of collision is:

A) somewhat inelastic.
B) elastic.
C) completely inelastic.

Answer 13

B) elastic.

Question 14

In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is:

A) perfectly elastic.
B) partially inelastic.
C) completely inelastic.
D) characterized by an increase in kinetic energy.
E) not possible because momentum is not conserved.

Answer 14

A) perfectly elastic.

Question 15

23) In the figure showing an isolated system, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is:

A) perfectly elastic.
B) partially inelastic.
C) completely inelastic.
D) characterized by an increase in kinetic energy.
E) not possible because momentum is not conserved.

Answer 15

E) not possible because momentum is not conserved.

Question 16

24) In the figure, determine the character of the collision. The masses of the blocks, and the velocities before and after, are shown. The collision is:

A) perfectly elastic.
B) partially inelastic.
C) completely inelastic.
D) characterized by an increase in kinetic energy.
E) not possible because momentum is not conserved.

Answer 16

C) completely inelastic.

Question 17

26) An egg falls from a bird’s nest in a tree and feels no effects due to the air. As it falls,

A) only its kinetic energy is conserved.
B) only its momentum is conserved.
C) both its kinetic energy and its momentum are conserved.
D) only its mechanical energy is conserved.
E) both its mechanical energy and its momentum are conserved.

Answer 17

D) only its mechanical energy is conserved.

Question 18

27) A railroad car collides with and sticks to an identical railroad car that is initially at rest. After the collision, the kinetic energy of the system

A) is the same as before.
B) is half as much as before.
C) is one third as much as before.
D) is one fourth as much as before.
E) is one quarter as much as before.

Answer 18

B) is half as much as before.

Question 19

28) A rubber ball bounces off of a wall with an initial speed v and reverses its direction so its speed is v right after the bounce. As a result of this bounce, which of the following quantities of the ball are conserved? (There could be more than one correct choice.):

A) the kinetic energy of the ball
B) the momentum of the ball
C) both the momentum and the kinetic energy of the ball
D) None of the above quantities are conserved.

Answer 19

A) the kinetic energy of the ball

Question 20

29) On a horizontal frictionless air table, a puck runs into an ideal horizontal spring that is fastened to the table. The puck compresses the spring by 15 cm before coming to rest. During the compression process, which quantities are conserved?

A) only the momentum of the puck
B) only the kinetic energy of the puck
C) only the mechanical energy (kinetic plus potential) of the puck
D) the momentum and the mechanical energy of the puck
E) the momentum and the kinetic energy of the puck

Answer 20

C) only the mechanical energy (kinetic plus potential) of the puck

Question 21

65) When a rigid object rotates about a fixed axis, what is true about all the points in the object? (There could be more than one correct choice.)

A) They all have the same angular speed.
B) They all have the same tangential speed.
C) They all have the same angular acceleration.
D) They all have the same tangential acceleration.
E) They all have the same radial acceleration.

Answer 21

A) They all have the same angular speed.

C) They all have the same angular acceleration.

Question 22

66) Two children, Ahmed and Jacques, ride on a merry-go-round. Ahmed is at a greater distance from the axis of rotation than Jacques. Which of the following are true statements? (There could be more than one correct choice.)

A) Jacques has a greater angular speed than Ahmed.
B) Jacques and Ahmed have the same angular speed.
C) Jacques has a smaller angular speed than Ahmed.
D) Ahmed has a greater tangential speed than Jacques.
E) Jacques and Ahmed have the same tangential speed.

Answer 22

B) Jacques and Ahmed have the same angular speed.

D) Ahmed has a greater tangential speed than Jacques.

Question 23

68) The figure shows scale drawings of four objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the greatest moment of inertia when rotated about an axis perpendicular to the plane of the drawing at point P?

A) A
B) B
C) C
D) D
E) The moment of inertia is the same for all of these objects.

Answer 23

B) B

Question 24

69) Consider a uniform hoop of radius R and mass M rolling without slipping. Which is larger, its translational kinetic energy or its rotational kinetic energy?

A) Translational kinetic energy is larger.
B) Rotational kinetic energy is larger.
C) Both are equal.
D) You need to know the speed of the hoop to tell.

Answer 24

C) Both are equal.

Question 25

70) Consider a solid uniform sphere of radius R and mass M rolling without slipping. Which form of its kinetic energy is larger, translational or rotational? A) Translational kinetic energy is larger. B) Rotational kinetic energy is larger. C) Both are equal. D) You need to know the speed of the sphere to tell.

Answer 25

A) Translational kinetic energy is larger.

Question 26

71) A disk and a hoop of the same mass and radius are released at the same time at the top of an inclined plane. If both are uniform, which one reaches the bottom of the incline first if there is no slipping? A) The hoop B) The disk C) Both reach the bottom at the same time.

Answer 26

B) The disk

Question 27

72) Suppose a uniform solid sphere of mass M and radius R rolls without slipping down an inclined plane starting from rest. The linear velocity of the sphere at the bottom of the incline depends on A) the mass of the sphere. B) the radius of the sphere. C) both the mass and the radius of the sphere. D) neither the mass nor the radius of the sphere.

Answer 27

D) neither the mass nor the radius of the sphere.

Question 28

73) Suppose a solid uniform sphere of mass M and radius R rolls without slipping down an inclined plane starting from rest. The angular velocity of the sphere at the bottom of the incline depends on A) the mass of the sphere. B) the radius of the sphere. C) both the mass and the radius of the sphere. D) neither the mass nor the radius of the sphere.

Answer 28

B) the radius of the sphere.

Question 29

74) A uniform ball is released from rest on a no-slip surface, as shown in the figure. After reaching its lowest point, the ball begins to rise again, this time on a frictionless surface. When the ball reaches its maximum height on the frictionless surface, it is: A) higher than when it was released. B) lower than when it was released. C) at the same height from which it was released. D) It is impossible to tell without knowing the mass of the ball. E) It is impossible to tell without knowing the radius of the ball.

Answer 29

B) lower than when it was released.

Question 30

75) Two forces produce equal torques on a door about the door hinge. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Both forces are applied perpendicular to the door. Which force has a greater magnitude? A) the first force (at the midpoint) B) the second force (at the doorknob) C) The two forces are equal.

Answer 30

A) the first force (at the midpoint)

Question 31

76) As shown in the figure, a given force is applied to a rod in several different ways. In which case is the torque about the pivot P due to this force the greatest? A) 1 B) 2 C) 3 D) 4 E) 5

Answer 31

A) 1

Question 32

77) Five forces act on a rod that is free to pivot at point P, as shown in the figure. Which of these forces is producing a counter-clockwise torque about point P? (There could be more than one correct choice.) A) force A B) force B C) force C D) force D E) force E

Answer 32

C) force C

Question 33

78) The rotating systems shown in the figure differ only in that the two identical movable masses are positioned a distance r from the axis of rotation (left), or a distance r/2 from the axis of rotation (right). If you release the hanging blocks simultaneously from rest, A) the block at the left lands first. B) the block at the right lands first. C) both blocks land at the same time.

Answer 33

B) the block at the right lands first.

Question 34

79) A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms, A) her moment of inertia decreases and her angular speed increases. B) her moment of inertia decreases and her angular speed decreases. C) her moment of inertia increases and her angular speed increases. D) her moment of inertia increases and her angular speed decreases. E) her moment of inertia increases and her angular speed remains the same.

Answer 34

D) her moment of inertia increases and her angular speed decreases

Question 35

80) A spinning ice skater on extremely smooth ice is able to control the rate at which she rotates by pulling in her arms. Which of the following statements are true about the skater during this process? (There could be more than one correct choice.) A) Her angular momentum remains constant. B) Her moment of inertia remains constant. C) Her kinetic energy remains constant. D) She is subject to a constant non-zero torque.

Answer 35

A) Her angular momentum remains constant.

Question 36

81) When is the angular momentum of a system constant? A) Only when its total kinetic energy is constant. B) Only when no net external force acts on the system. C) Only when the linear momentum and the energy are constant. D) Only when no net external torque acts on the system. E) Only when the moment of inertia is constant.

Answer 36

D) Only when no net external torque acts on the system.

Question 37

105) When a car is weighed, it is driven slowly on a horizontal floor over a scale that records a reading as the front wheels go over the scale, and then records a second reading as the rear wheels go over the scale. The weight of the car is equal to A) the weight under the front wheels. B) the weight under the rear wheels. C) the average of the two weights. D) the sum of the two weights. E) the difference of the two weights.

Answer 37

D) the sum of the two weights.

Question 38

106) A croquet mallet balances when suspended from its center of mass, as shown in the left part of the figure. If you cut the mallet into two pieces at its center of mass, as shown in the right part of the figure, how do the masses of the two pieces compare? (There could be more than one correct choice.) A) The masses are equal. B) The piece with the head of the mallet has the greater mass. C) The piece with the head of the mallet has the smaller mass. D) It is impossible to tell.

Answer 38

B) The piece with the head of the mallet has the greater mass. D) It is impossible to tell. <-- listed as a correct answer but I would double check

Question 39

115) As shown in the figure, fluid fills a container having several sections. At which of the indicated points is the pressure greatest? A) A B) B C) C D) D E) The pressure is the same at each of the labeled points.

Answer 39

E) The pressure is the same at each of the labeled points.

Question 40

116) Consider a brick that is totally immersed in water, with the long edge of the brick vertical. The pressure on the brick is A) the same on all surfaces of the brick. B) greatest on the face with largest area. C) greatest on the top of the brick. D) greatest on the sides of the brick. E) greatest on the bottom of the brick.

Answer 40

E) greatest on the bottom of the brick.

Question 41

117) An air bubble underwater has the same pressure as that of the surrounding water. As the air bubble rises toward the surface (and its temperature remains constant), the volume of the air bubble A) increases. B) decreases. C) remains constant. D) increases or decreases, depending on the rate it rises.

Answer 41

A) increases.

Question 42

118) A cubical block of stone is lowered at a steady rate into the ocean by a crane, always keeping the top and bottom faces horizontal. Which one of the following graphs best describes the gauge pressure p on the bottom of this block as a function of time t if the block just enters the water at time t = 0 s?

Answer 42

(A)

Question 43

119) A cubical block of stone is lowered at a steady rate into the ocean by a crane, always keeping the top and bottom faces horizontal. Which one of the following graphs best describes the absolute (total) pressure p on the bottom of this block as a function of time t if the block just enters the water at time t = 0 s?

Answer 43

Question 44

120) If atmospheric pressure increases by an amount Δp, which of the following statements about the pressure in a lake is true? (There could be more than one correct choice.) A) The absolute (total) pressure does not change. B) The absolute (total) pressure increases, but by an amount less than Δp. C) The absolute (total) pressure increases by Δp. D) The gauge pressure increases by Δp. E) The gauge pressure does not change.

Answer 44

C) The absolute (total) pressure increases by Δp. E) The gauge pressure does not change.

Question 45

121) A closed cubical chamber resting on the floor contains oil and a piston. If you push down on the piston hard enough to increase the pressure just below the piston by an amount Δp, which of the following statements is correct? (There could be more than one correct choice.) A) The pressure everywhere in the oil will increase by Δp. B) The pressure at the bottom of the oil will increase by more than Δp. C) The pressure at the top of the oil will increase by less than Δp. D) The pressure on the sides of the chamber will not increase. E) The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber.

Answer 45

A) The pressure everywhere in the oil will increase by Δp. E) The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber.

Question 46

122) The water pressure to an apartment is increased by the water company. The water enters the apartment through an entrance valve at the front of the apartment. Where will the increase in the static water pressure be greatest when no water is flowing in the system? A) at a faucet close to the entrance valve B) at a faucet far from the entrance valve C) It will be the same at all faucets. D) There will be no increase in the pressure at the faucets.

Answer 46

C) It will be the same at all faucets.

Question 47

123) A waiter fills your water glass with ice water (containing many ice cubes) such that the liquid water is perfectly level with the rim of the glass. As the ice melts, A) the liquid-water level remains flush with the rim of the glass. B) the liquid water level rises, causing water to run down the outside of the glass. C) the liquid-water level decreases.

Answer 47

A) the liquid-water level remains flush with the rim of the glass.

Question 48

124) A spherical ball of lead (density 11.3 g/cm3) is placed in a tub of mercury (density 13.6 g/cm3). Which answer best describes the result? A) The lead ball will float with about 83% of its volume above the surface of the mercury. B) The lead ball will float with its top exactly even with the surface of the mercury. C) The lead ball will float with about 17% of its volume above the surface of the mercury. D) The lead will sink to the bottom of the mercury.

Answer 48

C) The lead ball will float with about 17% of its volume above the surface of the mercury.

Question 49

125) A wooden block contains some nails so that its density is exactly equal to that of water. If it is placed in a tank of water and released from rest when it is completely submerged, it will A) rise to the surface. B) sink to the bottom. C) remain where it is released.

Answer 49

C) remain where it is released.

Question 50

126) A boat loaded with rocks is floating in a swimming pool. If the rocks are thrown into the pool, the water level in the pool, after the rocks have settled to the bottom, A) rises. B) falls. C) stays the same.

Answer 50

B) falls.

Question 51

127) Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water. Where is the buoyant force greater on the boat? A) in salt water B) in fresh water C) The buoyant force is the same in both cases.

Answer 51

C) The buoyant force is the same in both cases.

Question 52

128) A 10-kg piece of aluminum sits at the bottom of a lake, right next to a 10-kg piece of lead, which is much denser than aluminum. Which one has the greater buoyant force on it? A) the aluminum B) the lead C) Both have the same buoyant force. D) It cannot be determined without knowing their volumes.

Answer 52

A) the aluminum

Question 53

129) As a rock sinks deeper and deeper into water of constant density, what happens to the buoyant force on it if it started above the surface of the water? A) The buoyant force keeps increasing steadily. B) The buoyant force remains constant. C) The buoyant force first increases and then remains constant. D) The buoyant force steadily decreases.

Answer 53

C) The buoyant force first increases and then remains constant.

Question 54

Two objects, one of mass m and the other of mass 2m, are dropped from the top of a building. When they hit the ground

Answer 54

B. the heavier one will have twice the kinetic energy of the lighter one.

Question 55

A 35-N bucket of water is lifted vertically 3.0 m and then returned to its original position. How much work did gravity do on the bucket during this process?

Answer 55

0 J

Question 56

You carry a 7.0 kg bag of groceries 1.2 m above the level floor at a constant velocity of 75 cm/s across a room that is 2.3 m room. How much work do you do on the bag in the process?

Answer 56

0 J

Question 57

A 4.0-kg object is moving with speed 2.0 m/s. A 1.0-kg object is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?

Answer 57

Both objects travel the same distance.

Question 58

Person X pushes twice as hard against a stationary brick wall as person Y. Which one of the following statements is correct?

Answer 58

Both do zero work

Question 59

A freight car moves along a frictionless level railroad track at constant speed. the car is open on top. A large load of coal is suddenly dumped into the car. What happens to the velocity of the car?

Answer 59

It decreases

Question 60

Two objects collide and bounce off each other, kinetic energy

Answer 60

is conserved only if the environment is frictionless

Question 61

If a light beach ball rolling with a speed of 6.0m/s collides with a heavy exercise ball at rest, the beach ball's speed after the collision will be, approximately,

Answer 61

C. 6.0 m/s

Question 62

In an elastic collision, if the momentum is conserved, then which of the following statements is true about kinetic energy?

Answer 62

kinetic energy is also conserved

Question 63

As you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it?

Answer 63

B)down

Question 64

A solid sphere, solid cylinder, and a hollow pipe all have equal masses and radii. If the three of them are released simultaneously at the top of an inclined plane and do not slip, which one will reach the bottom first?

Answer 64

A)sphere

Question 65

An object is attached to a vertical spring and bobs up and down between points A and B. Where is the object located when its kinetic energy is a maximum?

Answer 65

midway between A and B

Question 66

In simple harmonic motion, when is the speed the greatest? (There could be more than one correct choice.)

Answer 66

C. when the magnitude of the acceleration is a minimum E. when the potential energy is a zero

Question 67

If we double the frequency of a system undergoing simple harmonic motion, which of the following statements about that system are true? (There could be more than one correct choice.)

Answer 67

B)The angular frequency is doubled. D)The period is reduced to one-half of what it was.

Question 68

The total mechanical energy of a simple harmonic oscillating system is

Answer 68

E)a non-zero constant.

Question 69

A simple harmonic oscillator oscillates with frequency f when its amplitude is A. If the amplitude is now doubled to 2A, what is the new frequency?

Answer 69

C)f

Question 70

A box is being moved with a velocity v by a force P (in the same direction as v) along a level horizontal floor. The normal force is N, the kinetic frictional force if f_k, and the weight is mg. Which one of the following statements is correct

Answer 70

P does positive work, N and mg do zero work, and f_k does negative work.

Question 71

Which of the following would NOT be one of the four fundamental forces of nature?

Answer 71

strong electron force & weak electromagnetic force

Question 72

True/False: If an object remains at rest, then both the net torque and the net force on the object MUST be zero.

Answer 72

True

Question 73

A tiger is running in a straight line. If we double both the mass and speed of the tiger, the magnitude of its momentum will increase by what factor?

Answer 73

4 (P=mv ; 2m2v => 4mv => 4P)

Question 74

When you apply the torque equation to an object in equilibrium, the axis about which torques are calculated

Answer 74

can be located anywhere.

Question 75

An object at rest begins to rotate with a constant angular acceleration. If this object rotates through an angle(theta) in time t, through what angle did it rotate in the time 2t?

Answer 75

4(theta) (theta= wt + (1/2)at^2

Question 76

Simple harmonic motion is defined by which of the following conditions?

Answer 76

The vibrations are the result of a linear restoring force & The vibrations occur about an equilibrium position.

Question 77

Water flows through a pipe. The diameter of the pipe at point B is larger than at point A. Where is the water pressure greatest?

Answer 77

at point B

Question 78

If both the mass of a simple pendulum and its length are doubled, the period will

Answer 78

increase by a factor of sqrt2 (T = 2pi sqrt(l/g))

Question 79

An object of mass M oscillates on the end of a spring. To triple the period, replace the object with one of mass

Answer 79

9M (T=2pi sqrt(M/K))

Question 80

A string of mass m is under tension, and the speed of a wave in the string is v. What will be the speed of a wave in the string if the mass of the string is increased to 4 m but with no change in the length or tension?

Answer 80

v/2 v = (theta) (Lg)^1/2 sin((g/L) t)

Question 81

Two steel wires have the same length and are under the same tension. But wire A has twice the diameter of wire B. Which of the following is true?

Answer 81

Wire B stretches four times as much as wire A.

Question 82

Two horizontal pipes are the same length, but pipe B has twice the diameter of pipe A. Water undergoes laminar flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe A is Q, what is the flow rate in pipe B?

Answer 82

16Q

Question 83

A heavy rock and a light rock are dropped from the same height and experience no significant air resistance as they fall. Which of the following statements about these rocks are correct? (There could be more than one correct choice.)

Answer 83

-Both rocks have the same speed when they reach the ground. -When they reach the ground, the heavier rock has more kinetic energy than the lighter rock.

Question 84

A heavy stone and a light stone are released from rest in such away that they both have the same amount of gravitational potential energy just as they are released. Air resistance is negligibly small. Which of the following statements about these stones are correct? (There could be more than one correct choice.)

Answer 84

-The initial height of the light stone is greater than the initial height of the heavy stone -Just as it reaches the ground, the light stone is traveling faster than the heavy stone. -The stones both have the same kinetic energy just as they reach the ground

Question 85

A heavy dart and a light dart are launched vertically by identical ideal springs. Both springs were initially compressed by the same amount. There is no significant air resistance. Which of the following statements about these darts are correct? (There could be more than one correct choice.)

Answer 85

-The light dart goes higher than the heavy dart. -At the maximum height, both darts have the same gravitational potential energy.

Question 86

A very elastic rubber ball is dropped from a certain height and hits the floor with a downward speed v. Since it is so elastic, the ball bounces back with the same speed v going upward. Which of the following statements about the bounce are correct?

Answer 86

The magnitude of the ball's momentum was the same just before and just after the bounce

Question 87

Consider two less-than-desirable options. In the first you are driving 30 mph and crash headon into an identical car also going 30 mph. In the second option you are driving 30 mph and crash head-on into a stationary brick wall. In neither case does your car bounce back from the thing it hits, and the collision time is the same in both cases. Which of these two situations would result in the greater impact force on your car?

Answer 87

The force would be the same in both cases

Question 88

If the answer to your calculation has units of kg ∙ m2/s, what type of quantity could it be?

Answer 88

angular momentum

Question 89

If the answer to your calculation has units of kg ∙ m2/s, what type of quantity could it be?

Answer 89

angular momentum

Question 90

When you ride a bicycle, in what direction is the angular velocity of the wheels?

Answer 90

to your left

Question 91

Which one of the following would be expected to have the smallest bulk modulus?

Answer 91

helium vapor

Question 92

A piece of iron sinks to the bottom of a lake where the pressure is 21 times what it is at the surface of the lake. Which statement best describes what happens to the volume of that piece of iron?

Answer 92

Its volume decreases slightly.

Question 93

A piece of iron sinks to the bottom of a lake where the pressure is 21 times what it is at the surface. Which statement best describes what happens to the density of that piece of iron?

Answer 93

Its density increases slightly

Question 94

Two blocks are made of the same material, but one has twice the volume of the other block. Which block will have the greater shear modulus?

Answer 94

It will be the same for both of them

Question 95

A steel ball sinks in water but floats in a pool of mercury, which is much denser than water. Where is the buoyant force on the ball greater?

Answer 95

floating on the mercury

Question 96

When you blow some air above a paper strip, the paper rises. This happens because

Answer 96

the air above the paper moves faster and the pressure is lower.

Question 97

If we double the frequency of a system undergoing simple harmonic motion, which of the following statements about that system are true? (There could be more than one correct choice.)

Answer 97

-The angular frequency is doubled. -The period is reduced to one-half of what it was (Period = 1/f = 1/2T)

Question 98

The figure shows a graph of the position (x) as a function of time t for a system undergoing simple harmonic motion. Which one of the following graphs represents the velocity of this system as a function of time?

Answer 98

B)

Question 99

The figure shows a graph of the velocity v as a function of time t for a system undergoing simple harmonic motion. Which one of the following graphs represents the acceleration of this system as a function of time?

Answer 99

B)

Question 100

The figure shows a graph of the position x as a function of time t for a system undergoing simple harmonic motion. Which one of the following graphs represents the acceleration of this system as a function of time?

Answer 100

A)

Question 101

In simple harmonic motion, when is the speed the greatest? (There could be more than one correct choice.)

Answer 101

-when the magnitude of the acceleration is a minimum -when the potential energy is a zero (x=0)

Question 102

In simple harmonic motion, when is the magnitude of the acceleration the greatest? (There could be more than one correct choice.)

Answer 102

-when the magnitude of the displacement is a maximum (x= +/- A) -when the potential energy is a maximum (x=+/-A) -when the kinetic energy is a minimum

Question 103

The total mechanical energy of a simple harmonic oscillating system is

Answer 103

A non-zero constant

Question 104

An object attached to an ideal spring executes simple harmonic motion. If you want to double its total energy, you could

Answer 104

double the force constant (spring constant) of the spring

Question 105

An object that hangs from the ceiling of a stationary elevator by an ideal spring oscillates with a period T. If the elevator accelerates upward with acceleration 2g, what will be the period of oscillation of the object?

Answer 105

T

Question 106

A mass on a spring undergoes SHM. When the mass passes through the equilibrium position, which of the following statements about it are true? (There could be more than one correct choice.)

Answer 106

-Its acceleration is zero. -Its elastic potential energy is zero. -Its kinetic energy is a maximum.

Question 107

A mass on a spring undergoes SHM. When the mass is at its maximum distance from the equilibrium position, which of the following statements about it are true?

Answer 107

Its speed is zero.

Question 108

An object is attached to a vertical spring and bobs up and down between points A and B. Where is the object located when its kinetic energy is a minimum?

Answer 108

at either A or B

Question 109

A ball swinging at the end of a massless string, as shown in the figure, undergoes simple harmonic motion. At what point (or points) is the magnitude of the instantaneous acceleration of the ball the greatest?

Answer 109

A and D

Question 110

Grandfather clocks are designed so they can be adjusted by moving the weight at the bottom of the pendulum up or down. Suppose you have a grandfather clock at home that runs slow. Which of the following adjustments of the weight would make it more accurate?

Answer 110

Raise the weight.

Question 111

Grandfather clocks are designed so they can be adjusted by moving the weight at the bottom of the pendulum up or down. Suppose you have a grandfather clock at home that runs fast. Which of the following adjustments of the weight would make it more accurate?

Answer 111

Lower the weight.

Question 112

A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator moves upward with constant acceleration?

Answer 112

The period decreases

Question 113

A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator moves downward with constant acceleration?

Answer 113

The period increases

Question 114

A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator moves upward with constant velocity?

Answer 114

The period does not change.

Question 115

A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How would the period of the pendulum change if the supporting chain were to break, putting the elevator into freefall?

Answer 115

The period becomes infinite because the pendulum would not swing

Question 116

A simple pendulum and a mass oscillating on an ideal spring both have period T in an elevator at rest. If the elevator now accelerates downward uniformly at 2 m/s2, what is true about the periods of these two systems?

Answer 116

The period of the pendulum would increase but the period of the spring would stay the same.

Question 117

A simple pendulum and a mass oscillating on an ideal spring both have period T in an elevator at rest. If the elevator now moves downward at a uniform 2 m/s, what is true about the 32 periods of these two systems?

Answer 117

Both periods would remain the same.

Question 118

What is the wavelength of the wave shown in the figure? A) 8 m. B) 4 m. C) 2 m. D) 1 m. E) It cannot be determined from the given information.

Answer 118

E) It cannot be determined from the given information

Question 119

What is the frequency of the wave shown in the figure?

Answer 119

0.5 Hz (2T=4 T=2 f=1/2 = 0.5)