Circular Motion

Unit Learning Targets I can differentiate between centripetal and centrifugal I can define period and frequency I can apply Newton’s laws to circular situations I can calculate the centripetal acceleration

This chapter is tricky

What is Newton’s First? An object in motion remains in motion unless acted upon by a force; an object at rest remains at rest unless acted upon by a force.

Nothing can turn unless A force causes the object to change it’s motion. The force must be in the direction of the turn Think about a mass on a string – as it turns, what direction is the force acting on it?

Turning is always caused by an inward force Which is the true force? Centripetal – inward force Centrifugal – outward force Why is centrifugal a word? Centrifugal force is what you think you feel as you move in a circle – it’s really just inertia People think they feel it, so they treat it like a real force

Conceptual understanding is key! Centripetal force is a general term for any force that causes circular motion (even if it’s just part of a circle, like a turning car) It’s always inward – toward the center of a circle It’s not its own force, it’s always caused by some other force (for example, tension on a mass on a string)

Unit Learning Targets I can differentiate between centripetal and centrifugal I can define period and frequency I can apply Newton’s laws to circular situations I can calculate the centripetal acceleration