Speed limits on roads increase safety - AQA - GCSE Physics - Question 3 - 2022 - Paper 1
Question 3
Speed limits on roads increase safety.
The braking distance of a car increases as the speed of the car increases.
Give two other factors that increase the braking ... show full transcript
Worked Solution & Example Answer:Speed limits on roads increase safety - AQA - GCSE Physics - Question 3 - 2022 - Paper 1
Step 1
Give two other factors that increase the braking distance of a car.
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Answer
Wet or icy road conditions.
Poor condition of brakes or tires.
Step 2
Explain why the driver's reaction time affects the thinking distance of a car.
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Answer
The thinking distance is the distance a car travels from the moment the driver realizes they need to stop until they apply the brakes. This distance is determined by the driver's reaction time. If the reaction time is longer, the car will travel a greater distance during this time before the brakes are even applied.
Step 3
Which of the following conclusions can be made using Figure 5? Tick (✓) two boxes.
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✓ Mean reaction time increases after drinking alcohol.
✓ The change in reaction time is not the same for all people after drinking alcohol.
Step 4
Calculate the minimum time it takes to travel 1.5 km without breaking the speed limit.
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Answer
We can use the formula: distance = speed × time.
Here, the distance is 1500 m and the speed limit is 20 m/s.
Rearranging the formula gives us:
t=speeddistance=20 m/s1500 m=75 s
Step 5
Explain why the average speed of a car between the cameras and the average velocity of the car between the cameras are different.
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Answer
Velocity is a vector quantity and depends on direction, while speed is a scalar quantity. The average speed is the total distance traveled divided by the time taken, whereas average velocity takes into account the direction of the journey. If the road is not straight or if the car changes lanes, the average speed may differ from the average velocity due to changes in direction.
