Question detail
A car with a mass of 1000 kg is moving at a speed of 20 m/s. Calculate the work done by the brakes if the car comes to a stop. Include the formula used Explain your answer using Energy transfer and braking and braking.
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
Type
exam_style
Style
Topic
Work done and energy transfer
Question
A car with a mass of 1000 kg is moving at a speed of 20 m/s. Calculate the work done by the brakes if the car comes to a stop. Include the formula used Explain your answer using Energy transfer and braking and braking.
Answer
The work done by the brakes is 200,000 J. The formula used is W = F x s, where the force is equal to the change in kinetic energy, which is 200,000 J.
Explanation
A strong answer should address apply proportional reasoning when comparing work done by different braking forces directly. Use the context of Energy transfer and braking within Work done and energy transfer, then state the relevant forces or motion reasoning with units where needed. The answer is correct when it names the key physics quantity, keeps scalar and vector quantities distinct, and links the conclusion back to the approved learning objective.
Common mistake
Proportional Reasoning in Work Done
Students often assume that if one braking force is twice another, the work done will also be twice, without considering the distance over which the force is applied.
To fix this, remember that work done is calculated as the product of force and distance. Ensure to compare both the force and the distance when applying proportional reasoning.
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