STANDARDPhysics-Laws of Motion

STANDARD Physics Friction MCQ Question

Type: MCQ-conceptual-Medium-Class 11

A block of mass m rests on a rough inclined plane. The coefficient of friction between the surface and the block is μ. At what angle of inclination θ of the plane to the horizontal will the block just start to slide down the plane?

Question diagram
A

= tan⁻¹μ

B

= cos⁻¹μ

C

= sin⁻¹μ

D

= sec⁻¹μ

Correct Answer

Option A

Detailed Explanation

The forces acting on the block include the gravitational force, normal force, and frictional force. The block will start to slide when the component of gravitational force parallel to the incline (mgsinθ) equals the maximum static friction (μmgcosθ). Solving for θ gives tanθ = μ, hence θ = tan⁻¹(μ).

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