Chapter 7 - Momentum

Question 1

What is the area under a force-time graph equal to

Answer 1

The impulse

Question 2

What happens to energy and momentum in a perfectly elastic collision?

Answer 2

Momentum and kinetic energy are both conserved. I.e. no energy is dissipated as heat or sound

Question 3

What happens to energy and momentum in an inelastic collision?

Answer 3

Some kinetic energy will be converted to other forms during the collision but momentum is still conserved

Question 4

What is the point of air bags, crumple zones and seatbelts in a collision?

Answer 4

They slow you down gradually, therefore reducing the change in momentum (impulse) that you experience

Question 5

Why are seatbelts risky in some cases? (2)

Answer 5

They can cause bruising during a crash
They can be dangerous for small children and if the seatbelt is seated at their neck can be fatal

Question 6

Why are airbags risky during a crash in some cases?

Answer 6

If not wearing a seatbelt, a passenger can hit a rapidly expanding airbag very quickly and can be seriously injured by the bag.
For a rear facing booster seat, an airbag can push the seat towards the car seat with a lot of force and kill the child