A 3 kg block is resting on a ramp inclined at 20 degrees above the horizontal. What is the magnitude of the normal force acting on the block?

Question

A 3 kg block is resting on a ramp inclined at 20 degrees above the horizontal. What is the magnitude of the normal force acting on the block?

Answer 1

The downward force of gravity can be resolved into two components, one parallel to the ramp and on perpendicular to the ramp. The perpendicular force is the normal force, From the geometry of the problem, the perpendicular (normal) force is m x g x cos (ramp angle). Substitute the given mass, acceleration of gravity, and the cosine of the angle into the equation and solve.

Incidentally, the component of the force parallel to the ramp is m x g x sin (ramp angle).