Question

A force of 10N acts on a body of mass 2kg for 3seconds , initially at rest.
1. Velocity acquired by the body
2. Change in momentum of the body

Answer 1

$$\begin{gathered} \mathrm{Acceleration}: \\ \mathrm{a}=\frac{\mathrm{F}}{\mathrm{m}} \\ =\frac{10}{2} \\ =5\mathrm{m}/{\mathrm{s}}^2 \\ \left(\mathrm{i}\right) \\ \mathbf{Velocity}\mathbf{}\mathbf{acquired}\mathbf{:} \\ \mathrm{v}=\mathrm{u}+\mathrm{at} \\ =0+\left(5\right)\left(3\right) \\ \mathbf{}\mathbf{=}\mathbf{15}\mathbf{}\mathbf{m}\mathbf{/}\mathbf{s} \\ \left(\mathrm{ii}\right) \\ \mathbf{Change}\mathbf{}\mathbf{of}\mathbf{}\mathbf{momenum}\mathbf{:} \\ △\mathrm{p}=\mathrm{m}\left(\mathrm{v}-\mathrm{u}\right) \\ =2\times \left(15-0\right) \\ \mathbf{=}\mathbf{30}\mathbf{}\mathbf{kg}\mathbf{.}\mathbf{m}\mathbf{/}\mathbf{s} \end{gathered}$$