Figure 7.22a shows the potential-energy function for the force Fx = -kx. Sketch the potential-energy function for the force Fx = +kx. For this force, is x = 0 a point of equilibrium? Is this equilibrium stable or unstable? Explain.

Solution 18DQ Step 1: For the force, F(x) = kx, The potential energy would be, 1 2 U(x) = x dx = k x2. The graph of this will look like,