The potential energy function for a system is given by:

u(x) = 3x^3 - 2x^2 - 6x

where x is in meters and u is in joules.
a) determine the force fx as a function of x
b) for what values of x is the force equal to zero
c) plot u(x) versus x and fx versus x, and indicate thepoints of stable and unstable equilibrium.
d) if a particle moves from x= 2m to x = 4m, find thechange in its kinetic energy. assume that the only force acting onthe particles is the force found in part (a).