The coefficient of static friction between the 2.90 kg crate and the 35.0° incline of Figure P4.41 is 0.260. What minimum force F must be applied to the crate perpendicular to the incline to prevent the crate from sliding down the incline?

Answer 1

x: mgsinα = F(fr)
y: N=mgcosα + F

mgsinα = F(fr) =μN =μ(mgcosα + F),

F =mgsinα/μ - mgcosα =
=mg(sinα/μ – cosα)