momentum

Question 1

what is the unit used 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

the total momentum before is equal to the 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 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 passengers safety during a collision

Answer 5

• passenger must decelerate from the vehicles 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