Question

An object of mass $1kg$ is at rest. A constant force of $10N$ is applied on it for 2 seconds. Find the work done by the force on the object.

• A. $200J$
• B. $20J$
• C. $16J$
• D. $180J$

Answer 1

The correct option is A $200J$

Given:
Force $F=10N$
Mass of the object, $m=1kg$
Time, $t=2s$
Initial velocity, $u=0$ (the object was initially at rest).
Let $a$ be the acceleration of the object.
We know that force, $F$ = $ma$
$\therefore$ $a=\frac{F}{m}$
Using the second equation of motion:
$s=ut+\frac{1}{2}a{t}^2$
Substituting the corresponding values , we get,
$s=0+\frac{1}{2}\frac{F}{m}{t}^2$
$=\frac{1}{2}\times \frac{10}{1}\times (2{)}^2$
$=20m$
Work done, $W=F\times s$
$\therefore W=F\times s=10\times 20=200J$
Therefore, the work done by the force is $200J$