Question

An ideal pendulum is often discussed when studying simple harmonic motion.

What are the conditions needed for an ideal pendulum? Check all that apply.

Gravitational force acts to pull the pendulum’s mass down.
The mass of the rod of the pendulum is evenly distributed along the rod.
The pivot on which the pendulum swings is frictionless.
The pendulum swings through its equilibrium position as a result of inertia.
Tension acts downward on the pendulum’s mass.

Answer 1

Select:
- Gravitational force acts to pull the pendulum’s mass down. (Yes.)
- The pivot on which the pendulum swings is frictionless. (Yes.)
- The pendulum swings through its equilibrium position as a result of inertia. (Yes — this is a consequence of the motion: momentum carries the bob through equilibrium.)

Do not select:
- The mass of the rod of the pendulum is evenly distributed along the rod. (No — an ideal/simple pendulum assumes a point mass and a massless/string or massless rigid rod.)
- Tension acts downward on the pendulum’s mass. (No — tension acts along the string/rod toward the pivot, not simply downward.)