There is a "cannon" pointing downwards with a spring inside where an object is inside and compressed up 1 meter. mass of object = 50.0kg k = 49050 height = 0 at bottom of cannon. Potential energy at start = mgh + 1/2kx^2 Kinetic energy at end = 1/2mv^2 I had to first solve for the object velocity as a function of height 'y' above the bottom of the cannon. This was: v(h) = sqrt(-981y^2 - 19.6y + 1001) The question now is to solve for the amount of power being put out as a function of height. We are given the answer of: p(h) = 49y * v(h), but I am to find this on my own. I know: P = w*t, w = change in kinetic energy The change in kinetic energy can be found pretty easily, but what do I do about time?