Question

The acceleration of a body sliding down an inclined surface is

Answer 1

the acceleration is downwards, in the rough surface f= nieuwe aR and R = MG cos theta ,if you put the values then you can find the value of a

Answer 2

Considering the fact that there is no friction (since its not stated in your problem)

If the angle of inclination is alpha

The force acting downwards along the incline will have a component of mg as

mg sin(alpha) comparing it using F=ma

mg sin (alpha) = ma

So, acceleration, a = g sin(alpha)