Question

The time taken by a body in sliding down a rough inclined plane of angle of inclination 45° is n times the time taken by the same body in slipping down a similar frictionless plane. The coefficient of dynamic friction between the body and the plane will be

(a)   1/(1–n²) 

(b)   1 – (1/n²)

(c)  √{1– (1/n²)}

(d)   √{1/(1–n²)}

Answer 1

Correct option   (b) 1 – (1/n²)

Explanation:

Acceleration when there is no friction is a = gsinθ and acceleration when friction is there is