Question

A body of mass 37 kg rests on a rough
horizontal surface. The mi
horizontal force required to just start the
motion is 68.5 N. In order to keep the
body moving with constant velocity, a
force of 43 N is needed. What is the value
of a) coefficient of static friction? and b)
coefficient of kinetic friction?​

Answer 1

Answer:

The coefficient of static friction is 0.19

The coefficient of kinetic friction is 0.12

Explanation:

Mass of the body M = 37 kg

Minimum force required to start the motion F = 68.5 N

Before the motion has started, the coefficient of friction acting will be the static coefficient of friction

Thus,

$F=\mu_s\times Mg$

$\implies \mu_s=\frac{F}{Mg}$

$\implies \mu_s=\frac{68.5}{37\times 9.8}$

$\implies \mu_s=0.19$

When the body is in motion, the friction force acting will be kinetic friction

Given that the force acting to keep the motion with constant velocity F' = 43 N

Therefore, the coefficient of kinetic friction will be given by

$F'=\mu_k\times Mg$

$\implies \mu_k=\frac{F}{Mg}$

$\implies \mu_k=\frac{43}{37\times 9.8}$

$\implies \mu_k=0.12$

Hope this helps.