JEE Main Physics question
A block moving on a surface with velocity 20 ms⁻¹ comes to rest because of surface friction, over a distance of 40 m, with g = 10 ms⁻². The coefficient of dynamic friction is
Answer: (A)
Solution
μ = v²/(2gs) = 400/(2×10×40) = 400/800 = 0.5.