University:
Felician University
Course:
PHYS-355 | Advanced Topics in Physics
Academic year:

2020
Views:

123

Pages:

10
Author:

larbiwxcvbn

Centripetal force keeps an object in circular motion. Which moves faster on a merry-go-round, a horse near the outside rail or one near the inside rail? While a hamster rotates its cage about an axis, does the hamster rotate or does it revolve about the same axis? We begin to answer these questions by discussing the difference between rotation and revolution. Rotation and Revolution Two types of circular motion are rotation and revolution. Rotation and Revolution An axis is the straight line around which rotation takes place. • When an object turns about an internal axis—that is, an axis located within the body of the object—the motion is called rotation, or spin. • When an object turns about an external axis, the motion is called revolution. Rotation and Revolution The Ferris wheel turns about an axis. The Ferris wheel rotates, while the riders revolve about its axis. Rotation and Revolution Earth undergoes both types of rotational motion. • It revolves around the sun once every 365 ¼ days. • It rotates around an axis passing through its geographical poles once every 24 hours. Rotation and Revolution What are two types of circular motion? Rotational Speed Tangential speed depends on rotational speed and the distance from the axis of rotation. Rotational Speed The turntable rotates around its axis while a ladybug sitting at its edge revolves around the same axis. Rotational Speed Which part of the turntable moves faster—the outer part where the ladybug sits or a part near the orange center? It depends on whether you are talking about linear speed or rotational speed.