Analyze the motion of a simple swinging pendulum in terms of energy, (a) ignoring friction, and (b) taking friction into account. Explain why a grandfather clock has to be wound up.
Step 1 of 2:
a) When there is no friction, the pendulum will never stop swinging.. The reason for that is that all the potential energy gets converted to kinetic energy, and vice versa. When the pendulum swings from one extreme end to the other the pendulum rises to the same height on both sides of every swing, and reaches the same maximum speed at the bottom on every swing.