Question

A bus starts from the stop and takes $50$ seconds to attain the speed of $10$$\frac{m}{s}$. If the mass of the bus along with the passengers is $10000$ kg, the force applied (in N) by the engine of the bus to attain the speed of 10$\frac{m}{s}$ is ___ N.

Answer 1

Given, Initial velocity $u=0$, final velocity $v=10$ m/s, time $t=50$ second, Mass $m=10000$ kg,

We know that, Force $F=ma$ [Newton's Second Law]

$\Rightarrow F=m\frac{v-u}{t}$ [$\because v=u+at$ $\Rightarrow a=\frac{v-u}{t}$]
Therefore, $F=10000\frac{10-0}{50}$
$\Rightarrow 10000\times \frac{1}{5}$ $m{s}^{-2}$

$\Rightarrow F=2000$ $kgm{s}^{-2}$ or, $2000$ N

Thus, required force $=2000$ N