Question

A body undergoing a straight line motion is under the influence of source of constant power. How does its displacement very with time?

• A. 20 m
• B. 40 m
• C. 10$\sqrt{2}$ m
• D. $\frac{2P}{m}$
• E. 5$\sqrt{10}$ m

Answer 1

Answer: (D)

$\frac{2P}{m}$

Answer 2

The correct answer is (D): 20$\sqrt{2}$ m.
If P is the power of the source and t is the time, then by the work-energy theorem, the work done,
$W=P\times t=\frac{1}{2}mv^2,v^2=2Ptm, v\\{2P\frac{t}{m}\\},$ also
v=$\frac{ds}{dt}=ds=vdt.$
= $ds=\frac{2P}{m}$