Question

A body of mass 5 kg undergoes a change in speed from 20 to 0.20 m/s. The momentum of the body would

• A. increase by 99 kg m/s
• B. decrease by 99 kg m/s
• C. increase by 101 kg m/s
• D. decrease by 90 kg m/s

Answer 1

The correct option is B decrease by 99 kg m/s

Initial speed of the body $u=20m/s$

Final speed of the body $v=0.20m/s$

Thus change in momentum $\Delta p=m(v-u)$

$\therefore \Delta p=\left(5\right)(0.20-20)=-99kgm/s$

Thus momentum of the body decreases by $99kgm/s$.