Multiple choice

Consider the following situations:

  1. A labourer carrying bricks on his head on a level road from one place to another.
  2. A man rowing a boat upstream is at rest with respect to shore.
  3. When a body of mass moves with a uniform speed in a circle.
  4. When a car moves with a uniform speed on a smooth level road.

In which of the given situations is work done?

  1. Only 1

  2. Only 2

  3. Both 1 and 3

  4. Both 2 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In case 1, work is not done because the force applied and displacement makes the angle of 900. In case 2, the man is doing work because he is applying force result in respective motion between boat and stream. In case 3, the direction of the motion of body moving along the circular track is always at right angles to centripetal force. In case 4, weight of car and its displacement are at right angles.

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