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## Homework Statement

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) U

_{s}= KE + [tex]\Delta[/tex]U

_{int}(Final State)

1/2K[tex]\Delta[/tex]x

^{2}= 1/2mv

^{2}+[tex]\mu[/tex]mgcos[tex]\theta[/tex]*L

L being 4.15m