Question

A force acts for $10\text{sec}$ on a body of mass $100\text{kg}$ which was at rest, after which it ceases to act. If the body travels $160\text{m}$ in the next $8\text{sec}$, find the magnitude of the force.

• A. $100\text{N}$
• B. $200\text{N}$
• C. $300\text{N}$
• D. $400\text{N}$

Answer 1

The correct option is B $200\text{N}$

The body travels $160\text{m in}8\text{sec}$ , the velocity acquired is
$v=\frac{displacement}{time}$
$v=\frac{160}{8}=20\text{m/s}$
This velocity is attained in $10\text{sec}$.
So,
$v=u+at$
$20=0+a\left(10\right)$
$\Rightarrow a=2\text{m/s}$
$\therefore F=ma$
$=100\times 2$
$=200\text{N}$