Question

A man pushes a wall and fails to displace it. He does
A. Negative work
B. Positive but not maximum work
C. Maximum work
D. No work at all

Answer 1

Hint: We know that work done in displacing the object is equal to the product of the force applied on the object and the distance traveled by it in the direction of force applied. We will use this concept to find out the work done by the man.

Complete step by step answer:
Let us write the expression for work done by the man when he pushes the wall.
\[W = F \cdot d\] ……...……(1)
Here F is the amount of force applied by the man on the wall, and d is the distance traveled by the wall due to the application of force.
It is given that man fails to displace the wall that means distance traveled by the wall is zero.
\[d = 0\]
On substituting 0 for d in equation (1), we can write:
 \[\begin{array}{c}
W = F \cdot 0\\
 = 0
\end{array}\]
Therefore, from the above expression, we can conclude that the man's work when he pushes the wall and fails to displace it is equal to zero

So, the correct answer is “Option D”.

Additional Information:
The amount of force applied by the man on the wall is converted into the wall's potential energy and stored by it because we know that total energy is always constant.

Note:
Do not confuse that the man is pushing the wall that means some amount of work is being done; we have to go with the basic concept of work done to find its nature and value. We can remember the equation (1) to solve similar problems.