Topic 5- Momentum

Question 1

What is the unit for momentum?

Answer 1

Kg m/s

Question 2

In a closed system, what can be said about the momentum before and after a collision?

Answer 2

Total momentum before is equal to total momentum afterwards

Question 3

What quantity is equal to the force experienced in a collision?

Answer 3

The rate of change of momentum

Question 4

If an object’s change of momentum is fixed, what is the only way to reduce the force that the object experiences?

Answer 4

Increase the length of time over which the change of momentum occurs

Question 5

Explain how a seatbelt improves a passenger’s safety during a collision

Answer 5

• passenger must decelerate form vehicles velocity at impact to zero (the undergo a fixed change of momentum)
• the force they experience is equal to the rate of change of momentum
• seatbelts increase the time over which the force is applied, reducing the rate of change of momentum and therefore reducing the force experienced