1. The problem statement, all variables and given/known data An object of mass M = 4 kg slides from rest a distance d = 4 m down a frictionless inclined plane where it encounters a spring. It compresses the spring a distance D = 1 m before stopping. The inclined plane makes an angle q = 20° with the horizontal. 2. Relevant equations When the block just touches the spring, how much gravitational potential energy has it lost? U=53.7 J After the mass has fully compressed the spring, what is its total loss of gravitational potential energy? U=67.1 J What is the value of the spring constant? k=?? 3. The attempt at a solution U=Ui-Uf U=53.7-67.1=-13.4 U=(1/2)kx^2 k=2U/x^2 k=2(-13.4)/(5)^2 k=1.07???? the answer is wrong. am i suppose to use the conservation of mechanical energy? because i am lost.