Energy Problem involving Friction and Spring

AI Thread Summary
The discussion revolves around calculating the potential energy stored in a spring that launches a wooden block up an incline. The block, with a mass of 1.30 kg, is projected at an angle of 35 degrees and reaches a speed of 5.00 m/s after traveling 4.15 m. Participants emphasize the need to include gravitational potential energy in the energy conservation equation, as the block's height changes during its motion. The equation should account for kinetic energy, work done against friction, and the change in potential energy. The importance of correctly identifying all energy components in the system is highlighted for accurate calculations.
Chandasouk
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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 \muk = 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 + \DeltaUint (Final State)

1/2K\Deltax2 = 1/2mv2+\mumgcos\theta*L

L being 4.15m
 
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In the energy equation you have not included the potential energy.
 
PE is included because the block is at a location higher than it's initial position right?
 
What is the final position of the block from the horizontal surface?
ΔUint includes only the work done against the frictional force.
So one more term must be there in the energy equation.
 
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