Hey folks its me again! The problem at hand gives me a potential energy function ( V(x) ) that defines the height of a particle in motion. Next to the problem is a picture of a curvy graph that is y vs x. It asks to find the expression for the horizontal acceleration. This is what I did.. [PLAIN]http://img101.imageshack.us/img101/3631/prob2.gif [Broken] I started out with the conservation of Energy equation and solved for "v." Then I differentiated with respect to "t". I do not think this is correct however because "V" does not depend on "t" so, how could I differentiate "v" without getting zero? (Since no "t's" are in the equation and nothing depends on "t." Also, why would this be the horizontal acceleration? as far as I know, the "v" in the kinetic energy equation only gives speed, with no direction. So how could I get the horizontal direction?