A wooden block with mass 1.50 kg is placed against a compressed spring at the bottom of an incline of slope 30.0 degrees (point A). When the spring is realeased, it projects the block up the inline. At point B, a distance of 6.00 m up the incline from A, the block is moving up the incline at 7.00 m/s and is no longer in contact with the spring. The coefficient of kinetic friction between the block and incline is μk = 0.50. The mass of the spring is negligible. Calculate the amount of potential energy that was initially stored in the spring. Answer at the back of the book is 119 J. This question is from University Physics 11th edition ques. 7.73 from Chapter 7. I have been trying to do this question for like 3 hours and is sarting to piss me off . I am using the formula: (PEb + PEs + KE)i + Wother = (PEb + PEs + KE)f PEb= pot. enery. of block PEs =pot. energy of spring Woher= work other i= initial f= final Since there is no kE initial i said its 0 and since there is PEb & PEs final i said its 0. So I hae mgxsintheta + PEs + μmgcostheta = (1/2) mv^2 Plugged in values and tried to solve for PEs but can't get 119J. I have simiar problem due (with the values different) that is due in about a hour and half. So need help fast!