A wooden block with mass 1.30 kg is placed against a compressed spring at the bottom of a slope inclined at an angle of 35.0 degrees (point A). When the spring is released, it projects the block up the incline. At point B, a distance of 4.15 m up the incline from A, the block is moving up the incline at a speed of 5.00 m/s and is no longer in contact with the spring. The coefficient of kinetic friction between the block and incline is [tex]\mu[/tex]k = 0.450. The mass of the spring is negligible.
Calculate the amount of potential energy that was initially stored in the spring.
Take free fall acceleration to be g = 9.80 m/s^2.
I don't really know what to do.
I start by doing some energy graphs
(Initial) Us = KE + [tex]\Delta[/tex]Uint (Final State)
1/2K[tex]\Delta[/tex]x2 = 1/2mv2+[tex]\mu[/tex]mgcos[tex]\theta[/tex]*L
L being 4.15m