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 BExplanation:$W= \frac{1}{2}mv^{2}$ $\therefore$ $Pt= \frac{1}{2}mv^{2}$ $\therefore $ $v=\sqrt{\frac{2Pt}{m}}$ $=\sqrt{\frac{2\times0.5\times5}{0.2}}=5m/s$
