T5 momentum

Question 1

equation used to calculate an object’s momentum

Answer 1

momentum = mass x velocity

Question 2

unit used for momentum

Answer 2

kg m/s

kilogram meters per seconds

Question 3

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

Answer 3

the total momentum before is equal to the total momentum afterwards

Question 4

equation linking change in momentum, force and time

Answer 4

force x time = change in momentum

F Δt = mΔv

Question 5

what quantity is equal to the force experienced in a collision

Answer 5

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

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 collison

Answer 7

• passenger must decelerate from the vehicle’s velocity at impact to zero, meaning they 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