Question

A body of mass 10 kg is moving with a velocity of 20 m/s. A force is applied to it so that in 10 s it acquires a velocity of 40 m/s. The force applied is:

• A. 20 N
• B. 10 N
• C. 30 N
• D. 40 N

Answer 1

The correct option is A 20 N

Given : $m=10$ kg $u=20$ m/s $v=40$ m/s

$\Delta t=10$ s

Change in momentum $\Delta P=m(v-u)=10(40-20)=200$ kg.m/s

Thus force applied $F=\frac{\Delta P}{\Delta t}=\frac{200}{10}=20$ N