Question 1

The law of conservation of momentum is applicable to systems made up of objects described by which of the following?

Accepted Answer

The law of conservation of momentum applies to all systems regardless of scale (macroscopic or microscopic) and includes objects interacting through forces such as friction. It states that the total momentum of a closed system is constant if no external forces act on it.

Question 2

A 0.12-kg ball is moving at 6 m/s when it is hit by a bat, causing it to reverse direction and have a speed of 14 m/s.What is the change in the magnitude of the momentum of the ball?

Accepted Answer

The change in the magnitude of momentum is given by:

|Δp| = |p final - p initial|

where p is the momentum.

Initial momentum:

p initial = m*v initial = 0.12 kg * 6 m/s = 0.72 kg*m/s

Final momentum:

p final = m*v final = 0.12 kg * (-14 m/s) = -1.68 kg*m/s

Substituting into the equation:

|Δp| = |-1.68 kg*m/s - 0.72 kg*m/s| = 2.4 kg*m/s

Therefore, the answer is D.

Question 3

Ann the Astronaut weighs 60 kg.She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s.What speed does this give Ann as she moves toward the shuttle?

Accepted Answer

To conserve momentum, the momentum of the astronaut and the satellite before the push must be equal to the momentum of the astronaut and the satellite after the push. Since the satellite is much more massive, its initial velocity before the push is negligible, and we can approximate the momentum of the system before the push as just Ann's momentum, which is 60 kg x 0 m/s = 0 kg m/s. After the push, the total momentum of the system (Ann plus the satellite) is (60 kg + 350 kg) * V, where V is the velocity of the system after the push. Setting these two momenta equal, we get:

0 kg m/s = (60 kg + 350 kg) * V

Solving for V gives: V = -0.15 m/s

This negative velocity means that Ann is initially pushed backwards away from the shuttle. However, since she is tethered to the shuttle, she will eventually come to a stop and then be pulled back towards the shuttle.

To find Ann's velocity towards the shuttle after the push, we need to use the fact that the momentum of Ann plus the satellite before and after the push must also be equal to each other. We know that before the push, the momentum of Ann was 0 kg m/s. After the push, the momentum of Ann and the satellite is:

(60 kg * -0.15 m/s) + (350 kg * 0.90 m/s) = 255 kg m/s

To find Ann's velocity, we can use the equation for momentum:

momentum = mass x velocity

Solving for velocity gives:

velocity = momentum / mass

Plugging in the values we know, we get:

velocity = 255 kg m/s / 60 kg = 4.25 m/s

However, we need to remember that this velocity is negative, since it is pointing towards the shuttle. So the answer is:

Answer: B
 Ann's velocity towards the shuttle after pushing the satellite is 4.25 m/s, which is approximately 5.3 m/s (rounded to one decimal place).

Question 4

A crane drops a 0.30 kg steel ball onto a steel plate.The ball's speeds just before impact and after are 4.5 m/s and 4.2 m/s, respectively.If the ball is in contact with the plate for 0.030 s, what is the magnitude of the average force that the ball exerts on the plate during impact?

Accepted Answer

The answer of A crane drops a 0.30 kg steel...

Question 5

Lonnie pitches a baseball of mass 0.20 kg.The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Lonnie with a return speed of 60 m/s.If the bat is in contact with the ball for 0.050 s, what is the impulse experienced by the ball?

Accepted Answer

The answer of Lonnie pitches a baseball of mass 0.20...

Question 6

The dimensional equivalent of the quantity impulse in terms of the fundamental quantities (mass, length, time) is which of the following?

Accepted Answer

The answer of The dimensional equivalent of the quantity impulse...

Question 7

A 75-kg swimmer dives horizontally off a 500-kg raft.If the diver's speed immediately after leaving the raft is 4 m/s, what is the corresponding raft speed?

Accepted Answer

We can use conservation of momentum to solve this problem. 
Initial momentum of the system = 0 (since the raft and diver are initially at rest)
Final momentum of the system = (75 kg)(4 m/s) + (500 kg)V (where V is the velocity of the raft)
Setting the initial and final momenta equal: 
0 = (75 kg)(4 m/s) + (500 kg)V
Solving for V:
V = - (75 kg)(4 m/s) / (500 kg)
V = -0.6 m/s
The negative sign indicates that the raft is moving in the opposite direction to the diver, so we take the magnitude of the velocity, giving us choice C as the correct answer.

Question 8

Alex throws a 0.15-kg rubber ball down onto the floor.The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s.If the ball is in contact with the floor for 0.025 s, what is the magnitude of the average force applied by the floor on the ball?

Accepted Answer

The answer of Alex throws a 0.15-kg rubber ball down...

Question 9

If a glass of water is on a table with a piece of paper under it, it is relatively easy to pull the paper out without disturbing the glass very much if the pull is done very quickly.This is because, with a quick pull:

Accepted Answer

The key principle here is that by pulling the paper quickly, the time during which the force is applied is reduced, minimizing the chance for the glass to be disturbed significantly. This is not directly about the force being less, the momentum of the paper, or changes in the coefficient of kinetic friction, but rather about the short duration of the applied force.

Question 10

A 75-kg swimmer dives horizontally off a 500-kg raft.The diver's speed immediately after leaving the raft is 4.0 m/s.A micro-sensor system attached to the edge of the raft measures the time interval during which the diver applies an impulse to the raft just prior to leaving the raft surface.If the time interval is read as 0.20 s, what is the magnitude of the average horizontal force by diver on the raft?

Accepted Answer

The answer of A 75-kg swimmer dives horizontally off a...

Question 11

Jerome pitches a baseball of mass 0.20 kg.The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Jerome with a return speed of 60 m/s.What is the magnitude of change in the ball's momentum?

Accepted Answer

The answer of Jerome pitches a baseball of mass 0.20...

Question 12

The impulse experienced by a body is equivalent to its change in:

Accepted Answer

According to the impulse-momentum theorem, the impulse experienced by an object is equal to its change in momentum. Therefore, choice C, momentum, is the correct answer. Choices A and B are incorrect because they do not take into account the mass of the object, which is an important factor in determining the change in momentum. Choice D is incorrect because one of the choices must be valid.

Question 13

The dimensional equivalence of the quantity "momentum" in terms of the fundamental quantities (mass, length, time) is:

Accepted Answer

The answer of The dimensional equivalence of the quantity "momentum"...

Question 14

The units of impulse are equivalent to:

Accepted Answer

The units of impulse are equal to the units of force multiplied by time, which is kgm/s or kg m/s^2. This is equivalent to kgN*s or kgF*s, where N is the unit for force. Therefore, option C is the correct choice.

Question 15

A valid unit for momentum is which of the following?

Accepted Answer

The answer of A valid unit for momentum is which...

Question 16

A cannon of mass 1 500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 45$\degree$ above the horizontal.Find the recoil velocity of the cannon across the level ground.

Accepted Answer

We can use conservation of momentum to find the recoil velocity of the cannon. The initial momentum of the system (cannon + shell) is:

p_initial = (m_cannon + m_shell)v_initial

where m_cannon = 1500 kg is the mass of the cannon, m_shell = 10 kg is the mass of the shell, and v_initial = 200 m/s is the velocity of the shell.

The momentum of the system after the shell is fired can be split into two components: the recoil velocity of the cannon, v_recoil, and the velocity of the shell in the x-direction, vx:

p_final = (m_cannon)v_recoil + (m_shell)vx

Since the shell is fired at an angle of 45 degrees above the horizontal, its x-velocity is given by:

vx = v_initialcos(45) = 200√2/2 = 100√2 m/s

Therefore, the conservation of momentum equation becomes:

(m_cannon + m_shell)v_initial = (m_cannon)v_recoil + (m_shell)(100√2)

Solving for v_recoil, we get:

v_recoil = v_initial - (m_shell/m_cannon)(100√2)
          = 200 - (10/1500)(100√2)
          ≈ 0.937 m/s

So the answer is B) 0.94 m/s.

Question 17

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.25 * 10⁴ kg, how many bullets of mass 25 g would have to be fired at 250 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?

Accepted Answer

The answer of A machine gun is attached to a...

Question 18

A ball with original momentum +4.0 kg*m/s hits a wall and bounces straight back without losing any kinetic energy.The change in momentum of the ball is:

Accepted Answer

The answer of A ball with original momentum +4.0 kg*m/s...

Question 19

A car wash nozzle directs a steady stream of water at 1.5 kg/s, with a speed of 30 m/s, against a car window.What force does the water exert on the glass? Assume the water does not splash back.

Accepted Answer

The answer of A car wash nozzle directs a steady...

Question 20

Alex throws a 0.15-kg rubber ball down onto the floor.The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s.What is the change in the magnitude of the ball's momentum?

Accepted Answer

The change in the magnitude of the ball's momentum is equal to the final momentum minus the initial momentum. We can calculate the initial momentum as:

p initial = m*v initial = (0.15 kg)*(6.5 m/s) = 0.975 kg*m/s

And the final momentum as:

p final = m*v final = (0.15 kg)*(3.5 m/s) = 0.525 kg*m/s

Therefore, the change in momentum is:

Δp = p final - p initial = 0.525 kg*m/s - 0.975 kg*m/s = -0.45 kg*m/s

The negative sign indicates that the momentum of the ball decreased. However, we are interested in the magnitude of the change in momentum, so we take the absolute value:

|Δp| = |-0.45 kg*m/s| = 0.45 kg*m/s

And this is closest to answer choice B, 1.5 kg*m/s.

Quiz 6: Momentum and Collisions

The law of conservation of momentum is applicable to systems made up of objects described by which of the following?

A 0.12-kg ball is moving at 6 m/s when it is hit by a bat, causing it to reverse direction and have a speed of 14 m/s.What is the change in the magnitude of the momentum of the ball?

Ann the Astronaut weighs 60 kg.She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s.What speed does this give Ann as she moves toward the shuttle?

A crane drops a 0.30 kg steel ball onto a steel plate.The ball's speeds just before impact and after are 4.5 m/s and 4.2 m/s, respectively.If the ball is in contact with the plate for 0.030 s, what is the magnitude of the average force that the ball exerts on the plate during impact?

Lonnie pitches a baseball of mass 0.20 kg.The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Lonnie with a return speed of 60 m/s.If the bat is in contact with the ball for 0.050 s, what is the impulse experienced by the ball?

The dimensional equivalent of the quantity impulse in terms of the fundamental quantities (mass, length, time) is which of the following?

A 75-kg swimmer dives horizontally off a 500-kg raft.If the diver's speed immediately after leaving the raft is 4 m/s, what is the corresponding raft speed?

Alex throws a 0.15-kg rubber ball down onto the floor.The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s.If the ball is in contact with the floor for 0.025 s, what is the magnitude of the average force applied by the floor on the ball?

If a glass of water is on a table with a piece of paper under it, it is relatively easy to pull the paper out without disturbing the glass very much if the pull is done very quickly.This is because, with a quick pull:

Jerome pitches a baseball of mass 0.20 kg.The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Jerome with a return speed of 60 m/s.What is the magnitude of change in the ball's momentum?

The impulse experienced by a body is equivalent to its change in:

The dimensional equivalence of the quantity "momentum" in terms of the fundamental quantities (mass, length, time) is:

The units of impulse are equivalent to:

A valid unit for momentum is which of the following?

A cannon of mass 1 500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 45 $\degree$ above the horizontal.Find the recoil velocity of the cannon across the level ground.

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.25 * 10⁴ kg, how many bullets of mass 25 g would have to be fired at 250 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?

A ball with original momentum +4.0 kg*m/s hits a wall and bounces straight back without losing any kinetic energy.The change in momentum of the ball is:

A car wash nozzle directs a steady stream of water at 1.5 kg/s, with a speed of 30 m/s, against a car window.What force does the water exert on the glass? Assume the water does not splash back.

Alex throws a 0.15-kg rubber ball down onto the floor.The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s.What is the change in the magnitude of the ball's momentum?

Quiz 6: Momentum and Collisions

The law of conservation of momentum is applicable to systems made up of objects described by which of the following?

A 0.12-kg ball is moving at 6 m/s when it is hit by a bat, causing it to reverse direction and have a speed of 14 m/s.What is the change in the magnitude of the momentum of the ball?

Ann the Astronaut weighs 60 kg.She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s.What speed does this give Ann as she moves toward the shuttle?

A crane drops a 0.30 kg steel ball onto a steel plate.The ball's speeds just before impact and after are 4.5 m/s and 4.2 m/s, respectively.If the ball is in contact with the plate for 0.030 s, what is the magnitude of the average force that the ball exerts on the plate during impact?

Lonnie pitches a baseball of mass 0.20 kg.The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Lonnie with a return speed of 60 m/s.If the bat is in contact with the ball for 0.050 s, what is the impulse experienced by the ball?

The dimensional equivalent of the quantity impulse in terms of the fundamental quantities (mass, length, time) is which of the following?

A 75-kg swimmer dives horizontally off a 500-kg raft.If the diver's speed immediately after leaving the raft is 4 m/s, what is the corresponding raft speed?

Alex throws a 0.15-kg rubber ball down onto the floor.The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s.If the ball is in contact with the floor for 0.025 s, what is the magnitude of the average force applied by the floor on the ball?

If a glass of water is on a table with a piece of paper under it, it is relatively easy to pull the paper out without disturbing the glass very much if the pull is done very quickly.This is because, with a quick pull:

Jerome pitches a baseball of mass 0.20 kg.The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Jerome with a return speed of 60 m/s.What is the magnitude of change in the ball's momentum?

The impulse experienced by a body is equivalent to its change in:

The dimensional equivalence of the quantity "momentum" in terms of the fundamental quantities (mass, length, time) is:

The units of impulse are equivalent to:

A valid unit for momentum is which of the following?

A cannon of mass 1 500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 45 °\degree° above the horizontal.Find the recoil velocity of the cannon across the level ground.

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.25 * 104 kg, how many bullets of mass 25 g would have to be fired at 250 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?

A ball with original momentum +4.0 kg*m/s hits a wall and bounces straight back without losing any kinetic energy.The change in momentum of the ball is:

A car wash nozzle directs a steady stream of water at 1.5 kg/s, with a speed of 30 m/s, against a car window.What force does the water exert on the glass? Assume the water does not splash back.

Alex throws a 0.15-kg rubber ball down onto the floor.The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s.What is the change in the magnitude of the ball's momentum?

A cannon of mass 1 500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 45 $\degree$ above the horizontal.Find the recoil velocity of the cannon across the level ground.

A machine gun is attached to a railroad flatcar that rolls with negligible friction.If the railroad car has a mass of 6.25 * 10⁴ kg, how many bullets of mass 25 g would have to be fired at 250 m/s off the back to give the railroad car a forward velocity of 0.5 m/s?