The ball launcher in a pinball machine has a spring with a force constant of 1.10 N/cm (Fig. P5.71). The surface on which the ball moves is inclined 10.0° with respect to the horizontal. If the spring is initially compressed 4.00 cm, find the launching speed of a 0.100 kg ball when the plunger is released. Friction and the mass of the plunger are negligible. I converted all the cm to m (0.011 N/m and 0.04m). I apply the Conservation of mechanical energy. Initial KE and PE is 0. I also set final PE as 0 and solved for final velocity. So I tried (1/2)(k)(x^2) = (1/2)mv^2 however it is incorrect. I also try taking the final velocity and dividing it by cos 10. Wrong and not sure why I did that . What am I doing wrong?