Question

A block is placed on an inclined plane of inclination $\theta$. The angle of inclination is such that the block slides down the plane at a constant speed. The coefficient of kinetic friction between the block and the inclined plane is equal to

• A. $sin\theta$
• B. $cos\theta$
• C. $tan\theta$
• D. $cot\theta$

Answer 1

The correct option is C

$tan\theta$

As the block moves down the inclined plane at a constant velocity, its acceleration will be zero. Hence, the net force acting on it will be zero.
$mgsin\theta =\mu N\Rightarrow mgsin\theta =\mu mgcos\theta \Rightarrow \mu =tan\theta$
Hence, the correct choice is (c).