Finding Minimum Force Applied to Keep Objects Stationary?

[morgane28v]

The coefficient of static friction between the crate m1=3.00kg and the incline with θ=35° shown in the figure below is .300. What minimum force F must be applied to the crate perpendicular to the incline to prevent the crate from sliding down the incline?

mgsinθ
μsmgcosθ
f=ma

I don't quite get how the applied force fits into the equation. mgsinθ-μsmgcosθ+F=0?

 

[BOYLANATOR]

Your equation is almost right. You are not interested so much in F itself but the additional frictional force caused by F.

 

[morgane28v]

Okay thank you I got it!