The Highway Code gives this information about the stopping distance of a car - Edexcel - GCSE Physics - Question 1 - 2012 - Paper 1
Question 1
The Highway Code gives this information about the stopping distance of a car.
speed = 30 miles per hour
thinking distance = 9 m
braking distance = 14 m
(a) (i) Wh... show full transcript
Worked Solution & Example Answer:The Highway Code gives this information about the stopping distance of a car - Edexcel - GCSE Physics - Question 1 - 2012 - Paper 1
Step 1
What is the stopping distance?
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Answer
The stopping distance can be calculated by adding the thinking distance and the braking distance. Given that the thinking distance is 9 m and the braking distance is 14 m, we have:
Complete the sentence by putting a cross (✗) in the box next to your answer.
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Answer
The driver’s thinking distance is most likely to increase when A the driver is tired. This is because fatigue can slow reaction times, increasing the time taken for a driver to start braking.
Step 3
Calculate the momentum of the car.
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Answer
Momentum is calculated using the formula:
extMomentum=extMassimesextVelocity
Given that the mass of the car is 800 kg and its velocity is 3.0 m/s, we have:
extMomentum=800extkgimes3.0extm/s=2400extkgm/s
Step 4
Calculate the work done by the braking force.
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The work done by a force can be calculated using the formula:
extWork=extForceimesextDistance
In this case, the force is 600 N and the distance is 15 m, therefore:
extWork=600extNimes15extm=9000extJ
Step 5
Complete the sentence by putting a cross (✗) in the box next to your answer.
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Answer
The work done by the brakes during braking is equal to A the energy transferred, as work done is essentially the transfer of energy.