A wooden block with mass 1.75kg is placed against a compressed spring at the bottom of a slope inclined at an angle of 33.0? (point A). When the spring is released, it projects the block up the incline. At point B, a distance of 4.10m up the incline from A, the block is moving up the incline at a speed of 6.30m/s and is no longer in contact with the spring. The coefficient of kinetic friction between the block and incline is ?k = 0.55. The mass of the spring is negligible.
Calculate the amount of potential energy that was initially stored in the spring.