Moderate

A car is brought to rest in 5 s from a speed of 10 m / s. What is the average deceleration of the car?

Correct answer: C. 2 m/s2

  • A. 0.5 m/s2
  • B. 15 m/s2
  • C. 2 m/s2
  • D. 50 m/s2

Explanation

The average deceleration is calculated by the formula: Deceleration = (Final velocity - Initial velocity) / Time. Here, the initial velocity is 10 m/s, the final velocity is 0 m/s (since the car is brought to rest), and the time taken is 5 seconds. Therefore, the average deceleration is (0 m/s - 10 m/s) / 5 s = -2 m/s2. The negative sign indicates deceleration. Option C reflects this calculation accurately.Option A is incorrect because a deceleration of 0.5 m/s2 would require a much longer time to stop the car. Option B is incorrect as a deceleration of 15 m/s2 implies the car stopped in less than a second, which contradicts the given 5-second stopping time. Option D is incorrect because a deceleration of 50 m/s2 is unrealistically high for the given scenario and would indicate an almost instantaneous stop.

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