Hello!
For an object sliding down an inclined plane, there are two forces working on the object: The normal force and the force due to gravity.
Breaking the force due to gravity into its components, we get a force of:
Mgsinθ, parallel to the incline's slope. This is the NET force acting on the object, causing it to accelerate.
Since ∑F = m · a:
Mgsinθ = m · a
Divide by the mass:
a = gsinθ
