Acceleration and speed of 4kg block on frictionless 30° incline

[hasnain721]

Homework Statement

A block of wood of mass 4 kg is released from rest on a plane inclined at 30 degrees to the horizontal. Assuming that the surface can be modeled as smooth (no friction) calculate the acceleration of the block, and its speed after it has moved 3m

Homework Equations

equations of motion

The Attempt at a Solution

http://img174.imageshack.us/img174/2632/36018360et2.jpg

 

[Rudipoo]

Apply F = ma down the slope by calculating the component of the weight down the slope to find the acceleration. Then use v^2 = u^2 + 2as to find the velocity v after s = 3 metres. Hope this helps.