We know that the force formula for the inclined surface is given by:

F= m*g* sin(35) such that m= mass of the block , g is the gravity, and 35 is the inclined angle.

==> F = 20 * 9.8 * sin 35

==> F = 20*9.8*0.5736

**==> F = 112.42 N**

Then, the force that brings the block down is 112.42 N. Then we need an equal force but in the opposite direction.

**Then, the force needed to prevent the block from moving is (112.42)N is oppsit direction.**