Question

A man carries a box and waits for 5 minutes for the bus. What is the work done by the man?
A. $200J$
B. $100J$
C. $6000J$
D. $0J$

Answer 1

Hint:Work done is calculated by the formula-
$W = F \times d$
where, $W$ is the work done
$F$ is the force
$d$ is the displacement
The displacement done by the man is zero. So, put the values in their respective places in the formula of work done.

Complete step-by-step solution:The work is said to be done when a body moves due to the external force applied. Work can also be defined as an activity which includes the displacement and force in the direction of force. Work is denoted by $W$. It is a product of external force applied on an object and displacement done by the object.
Let the displacement done by the object be $d$ and external force on an object be $F$. Then, mathematically, we can represent work done as-
$W = F \times d \cdots (1)$
Unit of work done is Newton – metre which can also be termed as Joule which is denoted by $J.$
According to the question, it is given that the man is waiting for the bus hence, the displacement done by that man is zero.
$\therefore d = 0$
Now, putting the value of displacement which is zero in the equation $(1)$, we get the value of work done as-
$
  W = F \times 0 \\
   \Rightarrow W = 0J \\
 $
Therefore, the work done by the man waiting for the bus has not done any work.
Hence, option (D) is the correct answer.

Note:-
Work done in compressing a gas at constant temperature can be expressed as-
$W = PdV$
where, $P$ is the pressure
$dV$ is the change in volume
Work done by a torque can be expressed as-
$W = T\varphi $
where, $T = $ torque
$\varphi = $ angular displacement