Question

when the angle of
on between the block
• A block resting on an inclined plane begins to slide down the plane who
inclination is gradually increased to 30°. Then the coefficient of friction ber
and plane is closest to
(n) 0.50
(b) 0.58
(c) 0.72
(d) 0.87​

Answer 1

Answer:

( b ).

Explanation:

Here,

     Normal reaction R of the block is equal to one of the rectangular components of weight, R = mg cos30°.

The force acting downward is an another component of weight, it's mg sin30°.

Since no other force is acting, friction force = mg sin30° { in fact it's a little bit greater than this }

Therefore,

⇒ Co-efficient of friction = friction force / R

⇒ μ = mg sin30° / ( mg cos30° )

      = sin30° / cos30°

      = tan30°

      = 1 / √3

      ≈ 0.58

Therefore, option ( b ) is correct.