Question about spring compression

[chevyboy86]

A 12 kg block slides from rest down frictionless 35 degree incline and is stopped by spring w/ constant of 3.00x10^4 N/m. The block slides 3 m from the point of release to the point of rest against spring, how far has spring compressed?

Now I know this involves the equation Ws= 1/2kxmax2, but I am not sure where to go from there.

 

[Astronuc]

The block starts at rest and accelerates on a frictionless plane/incline. One could determined the acceleration of the block down the incline (F/m) and the velocity at the distance traveled.

Another way to do this is to apply conservation of energy. At the beginning, the energy of the block is simply gravitational potential energy (GPE). When block to the spring, it decreases in elevation, so its GPE changes, and that changes equals the increase in kinetic energy.

When the block compresses the spring, its kinetic energy is transformed into the springs potential energy.

http://hyperphysics.phy-astr.gsu.edu/hbase/pespr.html