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Chapter 6: Q6-1MCQ (page 138)

You push very hard on a heavy desk, trying to move it. You do work on the desk:

(a) whether or not it moves, as long as you are exerting a force.

(b) only if it starts moving.

(c) only if it doesn鈥檛 move.

(d) never鈥攊t does work on you.

(e) None of the above.

Short Answer

Expert verified

The obtained result is that you do work on the desk only if it starts moving.

Step by step solution

01

Work done on a heavy desk

One of the major misconceptions is that all the forces acting on a particular body, like a heavy desk, do work.

In order to achieve the work, the body has to move in the direction in which the force has been applied.

02

Determine when the work is done on the desk

When you are pushing a heavy desk, trying to move it from the rest position, the required work will take place only if the force acting on the desk has a component of motion. So, the work will be done if the heavy desk starts moving.

Thus, option (b) is the correct answer.

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