A mass is trapped on the x-axis. Its potential energy is given by U=-2x^3 -3x^2 +12x. Where x is i meters and U is in joules.
A) Determine an expression for the force that acts on the mass as a function of position.
B) Determine all positions of equilibrium (at equilibrium the net force=0).
C) Classify each equilibrium position as either stable or unstable.