Question 1

A 0.06 kg tennis ball travels to the right at $$75\ \mathrm{m\ s$$^{-1}$$}. A 3.5 kg $$brick is thrown to the right at $$1.5\ \mathrm{m\ s$$^{-1}$$}. $$Which object has the greater momentum?

Accepted Answer

Both have the same momentum, $$p = m v = 4.5\ \mathrm{kg\ m\ s$$^{-1}$$}.$$

Question 2

Which of the following best describes the principle of conservation of linear momentum?

Accepted Answer

The total momentum before an event is equal to the total momentum after, provided no external force acts.

Question 3

A stationary trolley B (mass $$80\ \mathrm{kg}) is $$hit head-on by trolley A (mass $$40\ \mathrm{kg}) $$traveling at $$3.0\ \mathrm{m\ s$$^{-1}$$}. $$After the collision, the trolleys stick together. What is their common velocity?

Accepted Answer

$$1.0\ \mathrm{m\ s$$^{-1}$$}$$

Question 4

A car of mass $$990\ \mathrm{kg}$$ traveling at $$10\ \mathrm{m\ s$$^{-1}$$}$$ collides with a stationary van of mass $$4200\ \mathrm{kg}. $$After the collision, the car moves at $$2\ \mathrm{m\ s$$^{-1}$$}. $$What is the velocity of the van after the collision?

Accepted Answer

$$1.89\ \mathrm{m\ s$$^{-1}$$}$$

Question 5

Which equation correctly defines linear momentum?

Accepted Answer

$$p = m v$$

Question 6

A cricket ball of mass $$0.058\ \mathrm{kg} is $$moving at $$30\ \mathrm{m\ s$$^{-1}$$} to $$the left. It is struck by a bat and returns to the right at $$20\ \mathrm{m\ s$$^{-1}$$}. $$What is the impulse delivered by the bat?

Accepted Answer

$$2.9\ \mathrm{kg\ m\ s$$^{-1}$$}$$

Question 7

Which of the following statements about impulse is correct?

Accepted Answer

Impulse is the product of force and the time for which it acts: $$J = F \Delta t.$$

Question 8

A hailstone and a raindrop both fall onto an umbrella. The hailstone has a larger mass and bounces off, while the raindrop does not. Which statement is true about the impulse applied to the umbrella?

Accepted Answer

The impulse from the hailstone is greater because it changes direction and has more mass.

Question 9

Which formula relates the resultant force to the rate of change of momentum?

Accepted Answer

$$F = \frac{\Delta p}{\Delta t}$$

Question 10

A ball of mass $$0.2\ \mathrm{kg} is $$moving at $$2\ \mathrm{m\ s$$^{-1}$$} to $$the right. It rebounds to the left at $$2\ \mathrm{m\ s$$^{-1}$$}. $$What is the change in momentum?

Accepted Answer

$$0.8\ \mathrm{kg\ m\ s$$^{-1}$$}$$

Question 11

In a collision, why is it important to consider the direction of velocity when calculating momentum?

Accepted Answer

Because momentum is a vector quantity and direction affects its sign.

Question 12

A force of $$10\ \mathrm{N}$$ acts on a $$2\ \mathrm{kg}$$ object for $$0.5\ \mathrm{s}. $$What is the change in momentum?

Accepted Answer

$$5\ \mathrm{kg\ m\ s$$^{-1}$$}$$

Question 13

Which of the following is a real-life example of impulse being used to reduce injury?

Accepted Answer

A cricket fielder moving their hands backwards while catching a ball.

Question 14

If a stationary object is hit and moves in the opposite direction to the incoming object, what is the sign of its velocity and momentum after the collision?

Accepted Answer

Both are negative if the original direction is taken as positive.

Question 15

A $$0.5\ \mathrm{kg}$$ ball is moving at $$4\ \mathrm{m\ s$$^{-1}$$}$$ and is brought to rest in $$0.2\ \mathrm{s} by a $$constant force. What is the magnitude of the force?

Accepted Answer

$$10\ \mathrm{N}$$

Question 16

Which of the following is NOT a correct application of the conservation of momentum?

Accepted Answer

Assuming momentum is conserved when an external force acts on the system.

Question 17

A $$1\ \mathrm{kg}$$ ball moving at $$5\ \mathrm{m\ s$$^{-1}$$}$$ collides with a stationary $$2\ \mathrm{kg}$$ ball. After the collision, the $$1\ \mathrm{kg}$$ ball moves at $$2\ \mathrm{m\ s$$^{-1}$$} in $$the same direction. What is the velocity of the $$2\ \mathrm{kg}$$ ball after the collision?

Accepted Answer

$$1.5\ \mathrm{m\ s$$^{-1}$$}$$

Question 18

Which of the following is the correct expression for the change in momentum?

Accepted Answer

$$\Delta p = p_f - p_i$$

Linear Momentum and Impulse: Principles, Applications, and Worked Examples

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