Q. If a body of mass $m$ is moving on a rough horizontal surface of coefficient of kinetic friction $\mu$, the net electromagnetic force exerted by surface on the body is
A) $mg\sqrt{1 + \mu^{2}}$
B) $\mu\ mg$
C) $mg$
D) $mg\sqrt{1 - \mu^{2}}$
Explanation
(a) The net electromagnetic force $= \sqrt{N^{2} + f^{2}}$
But $N = mg,f = \mu mg$
Force = $mg\sqrt{1 + \mu^{2}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.