Question

A 60 kg body is pushed horizontally with just enough force to start it moving across a floor and the same force continues to act afterwards. The coefficient of static friction and sliding friction are $0.5$ and $0.4$ respectively. The acceleration of the body is :

(A) $6 \mathrm{~m} / \mathrm{s}^{2}$

(B) $4.9 \mathrm{~m} / \mathrm{s}^{2}$

(C) $3.92 \mathrm{~m} / \mathrm{s}^{2}$

(D) $1 \mathrm{~m} / \mathrm{s}^{2}$

Answer 1

$a=\frac{f_{s}-f_{k}}{m}=\frac{\left(\mu_{s}-\mu_{k}\right) m g}{m}=(\mu s-\mu \mathrm{k}) g$

$=(0.5-0.4) 10=1 \mathrm{~m} / \mathrm{sec} 2$

So, The correct option of this question is (D).