JEE Main Physics question
A block is moving up an incline of inclination 60° with a velocity of 20 ms⁻¹ and stops after 2.00 s. If g = 10 ms⁻², then the approximate value of the coefficient of friction is
Answer: (C)
Solution
Retardation = v/t = 10 ms⁻². Going up: g(sinθ+μcosθ) = 10 ⟹ 0.866+0.5μ = 1 ⟹ μ = 0.268 ≈ 0.27.