5.7 Momentum (Higher)

Question 1

State the equation used to calculate an object’s momentum. (Higher)

Answer 1

Momentum = Mass x Velocity

Question 2

What is the unit used for momentum? (Higher)

Answer 2

kg m/s
kilogram metres per second

Question 3

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

Answer 3

The total momentum before the collision is equal to the total momentum after the collision

Question 4

State an equation linking change in momentum, force and time. (Higher)

Answer 4

Change in momentum = Force x Time

Question 5

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

Answer 5

The rate of change of momentum

Question 6

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

Answer 6

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

Question 7

Explain how a seatbelt improves a passenger’s safety during a collision. (Higher)

Answer 7

Passengers must decelerate from the vehicle’s velocity at impact to zero, meaning they undergo a fixed change in momentum. The force they experience is equal to the rate of change of momentum.

Seat belts increase the time over which the force is applied, reducing the rate of change of momentum and therefore reducing the force experienced.