question_answer

A board is balanced on a rough horizontal semi-circular log. Equilibrium is obtained with the help of addition of a weight to one of the ends of the board when the board makes an angle 6 with the horizontal. Coefficient of friction between the log and the board is

A) \[\tan \theta \]    

B)        \[\cot \theta \]

C) \[\cos \theta \]    

D)        \[sin\theta \]

Correct Answer: A

Solution :

[a] \[\mu N\cos \theta =N\sin \theta \] \[\mu =\tan \theta \]