Explanation:
For the given situation,
Frictional force = centripetal force
[tex]\mu mg = m \omega^{2}r[/tex]
Cancel out the common terms, we get
[tex]\mu = \frac{\omega^{2}r}{g}[/tex]
= [tex]\frac{(3.87)^{2} \times 0.12 m}{9.8}[/tex] (as 1 rpm = 0.10472 rad/sec)
= [tex]\frac{1.797}{9.8}[/tex]
= 0.183
thus, we can conclude that coefficient of static friction in the given situation is 0.183.