Question

A vehicle of $100$ kg is moving with a velocity of $5$ m/s. To stop it in $1/10$ sec, required force in opposite direction is ___________N

• A. $50$
• B. $500$
• C. $-5000$
• D. $1000$

Answer 1

The correct option is C $-5000$

Given initial velocity of the vehicle $u=5m/s$ and final velocity $v=0m/s$ as the vehicle stops and time taken for the vehicle to stop $t=\frac{1}{10}$s

We know force $F=mass\times acceleration$------(A)

Also acceleration $a=\frac{v-u}{t}$

Putting the above expression in A we get,

$F=100\times \frac{0-5}{\frac{1}{10}}=-5000N$

Negative sign implies that the force acts in the opposite direction of the motion