6.5.4.3 Forces and Braking

Question 1

What is the thinking distance?

Answer 1

The distance travelled between seeing a hazard (stimulus) and (fully) applying the brakes.

Question 2

What is the braking distance?

Answer 2

The distance travelled between (fully) applying the brakes and coming to a (complete) stop.

Question 3

What is definition of stopping distance?

Answer 3

The distance travelled between seeing a hazard (stimulus) and coming to a complete stop.

Question 4

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

Answer 4

thinking distance + braking distance = stopping distance

Question 5

The reaction time is the same as the thinking time. True or false?

Answer 5

True

Question 6

For a given speed the braking distance is greater.

True or false?

Answer 6

True

Question 7

What is a typical reaction time of a human?

Answer 7

0.2 - 0.9s

Question 8

What factors can affect a driver’s reaction time?

Answer 8

Tiredness
Drugs
Alcohol
Distractions

Question 9

How can you measure a person’s reaction time?

Answer 9

Drop a ruler; without warning; measure how far the ruler drops while reacting; convert to a time.
Have a (computer) screen that changes colour; suddenly; person has to tap a button; time measured between screen changing and button pressed.

Question 10

What will happen to the thinking and braking distance if a driver is distracted?

Answer 10

The thinking distance will increase

The braking distance will be the same

Question 11

What factors can affect the braking time of a car?

Answer 11

Wet or icy road
Worn brakes
Worn tyres
Mass of the car
Speed of the car

Question 12

What is the typical braking distance for a car travelling at 20 mph

Answer 12

6 m

Question 13

What is the typical braking distance for a car travelling at 70 mph

Answer 13

75 m

Question 14

If you double the speed, what happens to the braking distance?

Answer 14

It is quadrupled

Question 15

If you double the speed, what happens to the thinking distance?

Answer 15

It is doubled

Question 16

When the brakes are applied what happens in terms of forces and energy?

Answer 16

Work is done against friction; the kinetic store of the car decreases; the thermal store of the brakes increases.

Question 17

If the speed increases, what happens to the force required to stop in a certain distance?

Answer 17

It increases. The deceleration increases too.

Question 18

What are the dangers of driving at higher speeds?

Answer 18

Greater deceleration and braking force required to stop in a given distance; this could overheat the brakes; or lead to a loss of control of the car.