Question

A box is on the side of a hill inclined at 30°. The weight of the box is 40 pounds. What is the magnitude of the force required to keep the box from sliding down the hill?

Answer 1

We will have that the magnitude of the force required is:

$F=(20kg\ast9.8m/s^2)sin(30)\Rightarrow F=98N$

So, it will need at least 98 N to keep it from moving downwards.