Laws of Motion
Class 11 · Laws of Motion
Angle of Repose
Tilt the incline until the block just slides — see θ_repose = tan⁻¹(μ_s) emerge.
Key Notes
01
Angle of repose θ_r is the maximum incline angle at which a block stays at rest.
02
Above θ_r the down-incline component mg sinθ exceeds maximum static friction μ_s mg cosθ.
03
Equating gives θ_r = tan⁻¹(μ_s) — independent of mass.
Formulas
Angle of repose
Independent of mass.
Critical condition
Force balance at slip threshold.
Important Points
Once sliding begins, kinetic friction (μ_k < μ_s) takes over; net acceleration = g(sinθ − μ_k cosθ).
Sand piles, granaries, and conveyor belts all design around the angle of repose.
Angle of Repose notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 11 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.