Definition
Movement of an object along a curved path around a central point, where the object's direction is continuously changing even if its speed remains constant. Circular motion requires a force directed toward the center of the circle (centripetal force) to keep the object on its curved path; without that force, the object would travel in a straight line.
Plain English
Moving in a circle around a central point. Because the direction keeps changing, something has to keep pulling the object toward the center, otherwise it would fly off in a straight line.
Context Anchor
Seen in discussions of airplane turns, propeller rotation, and other rotating aircraft parts.
Derivation
From Latin circulus, meaning a small ring or circle. The term simply describes motion that traces out a circle.
Why Pilots Care
Understanding it explains the forces needed for safe, coordinated turns without altitude loss.
Analogy
Think of swinging a ball on a string in a circle. The string constantly pulls the ball inward; let go of the string and the ball flies off straight. In a turn, lift acts like the string.
Grounding Statement
An airplane in a level turn follows circular motion with lift supplying the inward pull.
Intuition Check
Circular motion does not mean the object must be speeding up or slowing down. If it keeps the same speed but keeps changing direction around a center, it is still circular motion.
Example Sentence 1
In a level turn, the aircraft is in circular motion, with the horizontal component of lift pulling it toward the center of the turn.
Example Sentence 2
Recognizing circular motion helps a pilot apply the correct bank to hold altitude.