Which term describes motion back and forth, such as a pendulum's path?

• A. Oscillation
• B. Rotation
• C. Vibration
• D. Flutter

Answer: (A)

When something moves back and forth around a central position, that repeating motion is called oscillation. A pendulum swings left and right around its lowest point, and this repeated swing is periodic, meaning it happens in a regular cycle over time. The motion involves energy shuttling between potential and kinetic forms as it swings away from and toward the center.

This is different from rotation, which is moving around a center or axis in a circular path. It’s also distinct from vibration, which usually refers to rapid, small-scale back-and-forth motion of a part rather than a full object tracing a swinging path. Flutter describes a fast, often turbulent motion caused by fluid forces. So the pendulum’s back-and-forth path best fits the idea of oscillation.