A Block of mass 2kg is on an a smooth inclined plane where sin@ = 3/5 at point A. Point B is 5 meters down the incline. Find the time it will take for the block to reach point given it is at rest at point A.

So to start with draw a free body diagram of a block on the slope at point A with the forces acting on it which will be the downward force of mass x g (2g) due to gravity and the reaction force 2gcos@. There are no frictional forces because the slope is smooth.

We have a couple of knowns already for the suvat equations, s = 5, u = 0, and we want to find t. so we can work out acceleration first using F=ma F=the force going down the slope 2gsin@. Therefore 2gsin@=2a, and by canceling the 2 on each side we get a=gsin@. we now have enough known to make a suvat equation for t. s=ut +0.5at^2 by substituting the numbers in we get 5=(0)t +3/10 t^2. so t is 4.08seconds