Question

A car of mass 1000 kg is moving with velocity of $10m/s$ and is acted upon by a forward force of 1000 N due to engine and retarding force of 500 N. The velocity after 10 seconds will be:

• A. $10m/s$
• B. $15m/s$
• C. $20m/s$
• D. zero

Answer 1

The correct option is B $15m/s$

Given : $m=1000$ kg $u=10$ m/s $t=10$ s

Applied force $F=1000$ N (forwards)

Retarding force $f=500$ N (backwards)

Acceleration of the car in forward direction $a=\frac{F-f}{m}=\frac{1000-500}{1000}=0.5$ $m/s^2$

Using $v=u+at$

$\therefore$ $v=10+0.5\times 10=15$ $m/s$