Question

A body of mass m, accelerates uniformly from rest to $v_1$ in time $t_1$. The instantaneous power delivered to the body as a function of time t is

• A. $\frac{mv_{1}t}{t_{1}}$
• B. $\frac{mv_{1}^{2}t}{t_{1}^{2}}$
• C. $\frac{mv_{1}t^{2}}{t_{1}}$
• D. $\frac{mv_{1}^{2}t}{t_{1}}$

Answer 1

Answer: (B)

$\frac{mv_{1}^{2}t}{t_{1}^{2}}$

Answer 2

Power $P = \vec{F}\cdot\vec{v} = mav = m\left(\frac{v_{1}}{t_{1}}\right)\left(\frac{v_{1}}{t_{1}}t\right) = \frac{mv_{1}^{2}t}{t_{1}^{2}}$