How does the pendulum to illustrate the conservation of energy?

When the pendulum is at it's highest point of it's swing, the pendulum is momentarily motionless as it changes direction. At this point, the pendulum has ZERO kinetic energy, and the most potential energy. When the pendulum is swinging down again, that potential energy is coverted into kinetic energy.

Since the energy is being converted, not created, the swinging pendulum illustrates the law of consevation of energy.

c the car's velocity increases constantly over time.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)