A 2 kg block rests on a 30° rough incline with μ = 0.5. A force F is applied perpendicular into the plane so that the block does not slip. If the minimum F is n/25 N, find n. Take g = 10 m s⁻².

Question

G1 Physics · Accepted Answer

Downslope weight component is mg sin30° = 10 N. Normal becomes N = mg cos30° + F = 10√3 + F. At limiting equilibrium, μN =10, so 0.5(10√3+F)=10. Hence F=20-10√3≈2.68 N. Therefore n≈25F≈67.