1. The problem statement, all variables and given/known data The graph I have posted is the result of using a motion sensor above a bouncing ball. I am asked to write a clear interpretation of the meaning of each parameter in the equation Y=At^2+Bt+C. 2. Relevant equations Y=Ax^2+Bt+C y=y0+v0t+1/2at^2 3. The attempt at a solution http://imageshack.us/photo/my-images/687/screenshot20110902at112.png/ I think relating the above two equations that B is the initial velocity and C is the initial position. "A" however is confusing me. Also if C is indeed the initial position I'm not quite sure I understand why it is negative.