Question

A force of $10N$ is applied on an object of mass $1kg$ for $2s$, which was initially at rest. What is the work done on the object by the force?

• A. $160J$
• B. $160J$
• C. $200J$
• D. $240J$

Answer 1

The correct option is C $200J$

Given: $Force,F=10N$
Mass, $m=1kg$
Time, $t=2s$
Initial velocity, $u=0$ (since the object is initially at rest)
Let the acceleration be $a$ and work done be $W$.
We know that, $F=m\times a$
$\Rightarrow 10=1\times a$
$\Rightarrow a=10m{s}^{-1}$
Substituting the value of $a$ in second equation of motion,
$s=ut+\frac{1}{2}a{t}^2$
$\Rightarrow s=0+\frac{1}{2}a{t}^2$
$\Rightarrow s=\frac{1}{2}\times 10\times (2{)}^2=20m$
Work done, $W=F\times s$
$\therefore W=10\times 20=200J$