forces - vehicle stopping distance

Question 1

what is stopping distance of a vehicle?

Answer 1

the total distance travelled from when the driver first spots the obstruction to when the car stops

Question 2

what are the 2 parts of stopping distance?

Answer 2

• thinking distance which is the distance travelled by car during the driver’s reaction time which is time taken for driver to spot the obstruction, make a decision and move their foot onto the brake.
• braking distance which is the distance car travels from driver applying the brakes to when the car stops

Question 3

the greater the speed of the vehicle,

Answer 3

the greater the stopping distance

Question 4

at 30mph, how long would it take family car to stop?

Answer 4

23m (six car lengths)

Question 5

what is reaction time in people?

Answer 5

it varies from person to person. typical range from 0.2s and 0.9s

Question 6

how do we measure person’s reaction time?

Answer 6

using a ruler. one person holds a ruler and volunteer places fingers on either side. ruler then dropped and volunteer has to catch it. the further it falls before being caught, the longer the reaction time. by measuring the distance that the ruler fell, we can look the reaction time up in a table

Question 7

why is it important for drivers to have the shortest possible reaction time?

Answer 7

to break if see obstruction, they need to be able to break quickly

Question 8

what factors increase reaction time?

Answer 8

• a longer reaction time than one who is alert
• alcohol and drugs
• distractions such as mobile phone

these also increase thinking distance

Question 9

what factors affect braking distance?

Answer 9

• wet or icy conditions reduce the friction between tyres and road, increasing braking distance
• worn tyres as it reduces friction between road and tyres
• worn brakes