1)

A particle of mass 0.2 kg moving in one dimension under a force that delivers a  constant power of 0.5W to the particle. If the initial speed (in ms-1)  of the particle is zero, the  speed (in ms-1) after 5s  is 


A) 4

B) 5

C) 8

D) 6

Answer:

Option B

Explanation:

$W= \frac{1}{2}mv^{2}$

  $\therefore$     $Pt= \frac{1}{2}mv^{2}$     $\therefore $    $v=\sqrt{\frac{2Pt}{m}}$

   $=\sqrt{\frac{2\times0.5\times5}{0.2}}=5m/s$