Question

A force of 42N is needed to start a box sliding across the floor. The weight of the box is 55N.

Answer 1

I think the right answer is c

Answer 2

Explanation:

It is given that,

Force applied to the box, F = 42 N

Weight of the box, W = 55 N

(a) Let f is the force of the friction acting on the box. The force of friction always opposes the motion of an object. It always equal to the applied force as :

f = -F = -42 N

(b) The frictional force is kinetic in nature because when the force is applied to the box it starts to move.

(c)  Let $\mu$ is the coefficient of friction. It is given by :

$\mu=\dfrac{f}{N}$

$\mu=\dfrac{42}{55}$

$\mu=0.76$

Hence, this is the required solution.