A particle moves along the x axis under the influence of a variable force F(x) = 6.8x^2 + 3.0x where the force is measured in Newtons and the distance in meters. What is the potential energy associated with this force at x = 2.0 m? Assume that U(x) = 0 J at x = 0 m. The formula I was trying to work with (from the book) is dU = -F*ds where U is the potential energy and s is the displacement.. Anyways,.. I went on ahead a plugged 2 into the equation, and I got 33.2, the Force.. then I multiplied the negative of that by 2.. the displacement, but apparently the answer is wrong. So I'm guessin the derivative of displacement is indeed different than the regular displacement..so I guess my question here is, how do i find the derivative of displacement? Sorry I'm jus now starting calculus this year and am not completely familiar with the concept yet..