JEE Main20202 Sep 2020Morning ShiftPhysicsLaws of MotionActual
A small block starts slipping down from a point B on an inclined plane A B , which is making an angle θ with the horizontal section B C is smooth and the remaining section C A is rough with a coefficient of friction μ . It is found that the block comes to rest as it reaches the bottom (point A) of the inclined plane. If B C = 2 A C , the coefficient of friction is given by μ = k tanθ . The value o
Correct answer
0
Step-by-step solution
Let A C = ℓ    ∴    B C = 2 ℓ    ∴    A B = 3 ℓ Apply work – Energy theorem W t + W m g = Δ K E mg ( 3 ℓ ) sin θ - μ mg cos θ ( ℓ ) = 0 + 0 μ mgcos θ ℓ = 3 mg / sin θ μ = 3 tan θ = ktan θ k = 3