• # question_answer A boy of mass m is sliding down a vertical pole by pressing it with a horizontal force F. If u. is the coefficient of friction between his palm & the pole, the acceleration with which he slides down is A)  1                                             B) $\frac{\mu F}{m}$ C) $g+\frac{\mu F}{m}$                   D) $g-\frac{\mu F}{m}$

Here normal contact force N = F friction force, $f=\mu N=\mu F$ So the FBD of boy is ma = mg-f$\Rightarrow$$a=g-\frac{\mu F}{m}$