A body of mass m accelerates uniformly from rest to ${\mathrm{v}}_1$ in time ${\mathrm{t}}_1$. As a function of time t, the instantaneous power delivered to the body is

• A

  $\frac{{\mathrm{mv}}_1\mathrm{t}}{{\mathrm{t}}_1}$

• B

  $\frac{{\mathrm{mv}}_1^2\mathrm{t}}{{\mathrm{t}}_1}$

• C

  $\frac{{\mathrm{mv}}_1{\mathrm{t}}^2}{{\mathrm{t}}_1}$

• D

  $\frac{{\mathrm{mv}}_1^2\mathrm{t}}{{\mathrm{t}}_1^2}$