Thinking & Braking Distances (AQA GCSE Physics: Combined Science)

• The stopping distance of a car is defined as:

The total distance travelled during the time it takes for a car to stop in response to some emergency

• It can be written as an equation involving two distances:

Stopping distance = Thinking distance + Braking distance

• Where:
  • Thinking distance = the distance travelled in the time it takes the driver to react (reaction time) in metres (m)
  • Braking distance = the distance travelled under the braking force in metres (m)
  • Stopping distance = the sum of the thinking distance and braking distance, in metres (m)

• For a given braking force, the greater the speed of the vehicle, the greater the stopping distance

ANSWER:  C

Step 1: Identify the different variables

• • Stopping distance = 40 m
  • Thinking distance = 14 m

Step 2: Rearrange the formula for stopping distance

Stopping distance = Thinking distance + Braking distance

Braking distance = Stopping distance – Thinking distance

Step 3: Calculate and identify the correct braking distance

• • Braking distance = 40 – 14 = 26 metres
  • Therefore, the answer is C