Stopping distances

Question 1

what is the thinking distance ?

Answer 1

distance travelled during a driver’s reaction time

Question 2

what factors affect the thinking distance ?

Answer 2

• alcohol
• drugs
• age
• tiredness
• distractions

Question 3

what is the braking distance ?

Answer 3

distance taken for a vehicle to stop under the force of the brakes

Question 4

what factors affect the braking distance ?

Answer 4

• wet or icy roads
• adverse weather conditions
• worn out brakes
• speed
• tyre conditions (if they’re bald, vehicle will skid on water)

Question 5

If there is a wet or icy road what will happen to the braking distance ?

Answer 5

This will increase as the frictional forces decrease, leading to a smaller deceleration
smaller force applied = smaller deceleration (Newton 2nd law)
vehicle takes more time to reduce velocity
- increased chance of skidding

Question 6

how does speed affect the braking distance ?

Answer 6

the faster a vehicle is travelling, the more kinetic energy it has - more work needs to be done to stop the vehicle, increasing the braking distance
greater braking force is needed to make it stop within a certain distance

Question 7

why might larger decelerations be more dangerous ?

Answer 7

larger decelerations require a larger braking force - which can overheat the brakes
if this happens they can fail - as temperature increases the friction decreases, driver can lose control

Question 8

how would a greater initial velocity affect the temperature of the brakes ?

Answer 8

the greater the velocity, the more kinetic energy there is to convert to heat energy during deceleration

Question 9

what is the stopping distance ?

Answer 9

distance it takes to stop a car

Question 10

how can we calculate the stopping distance ?

Answer 10

thinking distance + braking distance