JEE Main Physics question
A smooth block is released at rest on a 45° incline and then slides a distance d. The time taken to slide is n times as much to slide on a rough incline than on a smooth incline. The coefficient of friction is [AIEEE 2005, UP SEE 2005]
Answer: (A)
Solution
Since d = ½at², equal d gives / = /² = n². g sin45° = n²·g(sin45° − μcos45°) ⟹ 1 = n²(1−μ) ⟹ μ = 1 − 1/n².