P11 Car Safety and Momentum

Question 1

What is the equation linking force and change in momentum?

Answer 1

F=mΔv/Δt

Question 2

List 3 car safety features that prevent harm to passengers by reducing the rate of change in momentum:

Answer 2

-Crumple zones
-Airbags
-Seatbelts

Question 3

How do crumple zones reduce the chances of injury?

Answer 3

They increase the time taken for the momentum of the occupant to change, decreasing the overall force

Question 4

How do brakes work?

Answer 4

They create friction between the wheel and brake pad, which transfers energy from the kinetic stores of the wheels to the thermal stores of the brakes

Question 5

How do you calculate stopping distance?

Answer 5

Thinking distance + Braking distance

Question 6

What is the thinking distance?

Answer 6

The distance the vehicle travels during the driver’s reaction time

Question 7

What is the braking distance?

Answer 7

The distance the vehicle travels after the brakes are applied

Question 8

List 2 things that affect thinking distance:

Answer 8

-Speed
-Reaction time

Question 9

List 3 things that affect braking distance:

Answer 9

-Brake condition
-Tire condition (tread depth)
-Road surface