P13 Braking and momentum

Question 1

What is stopping distance?

Answer 1

Name given to the distance a vehicle travels to safely come to a stop after the driver has spotted a hazard

Question 2

What is thinking distance?

Answer 2

Distance a vehicle travels during drivers reaction time

Question 3

What is braking distance?

Answer 3

The distance vehicle travels once the brakes have been applied

Question 4

What is the relationship between stopping, thinking and braking distance?

Answer 4

stopping distance = thinking + braking

Question 5

What distance is proportional to the speed of the vehicle?

Answer 5

Thinking distance

Question 6

What factors can affect braking distance?

Answer 6

Speed
Road conditions
Icey roads
Conditions of tyres
Conditions of brakes

Question 7

What is the definition of one joule of work?

Answer 7

The work done when 1N of force causes 1m of displacement

Question 8

What is the law of conservation of momentum?

Answer 8

In a closed system, total momentum before an event is equal to total momentum before it

Question 8

How is the force acting on an object related to its momentum?

Answer 8

force acting on an object = rate of change of momentum

Question 9

Why do brakes get hot during a sudden stop?

Answer 9

Cars kinetic energy transfers to friction when the brakes are applied. Causing to an excess in thermal energy

Question 9

Examples of safety features which work by increasing the time taken for a change in momentum

Answer 9

Air bags
Seatbelts
Cycle helmets
Cushioned surfaces in playgrounds