# Chapter 10 CIRCULAR MOTION

## Presentation on theme: "Chapter 10 CIRCULAR MOTION"— Presentation transcript:

Chapter 10 CIRCULAR MOTION
Centripetal Vs Centrifugal

Rotation vs Revolution
Rotation: an object spins about an internal axis The Earth rotates on its axis once every 24 hours Revolution: movement around an external axis The earth revolves around the sun once every days (1 year)

Rotational Speed Period: time to complete one full rotation; measured in seconds Frequency: rotations per second (minute, hour); measured in hertz (sec-1) or rpm Rotational speed is the same thing as frequency

Centripetal Force Law Of Inertia: objects naturally move in straight paths Centripetal Force is a force applied at 90o to the path of an object causing it to curve (move in a circle) Force and acceleration at right angles to velocity

Measuring Centripetal Force
Force = mass x acceleration Fc = m ac Measured in newtons (N) Centripetal Acceleration = velocity squared/ radius ac = v2/ r Measured in m/s2

Real Force vs Fictitious Force
Centrifugal Force Fictitious Actually inertia: resistance to moving in a circle Newton’s 3rd Law Simulated Gravity: carnival rides; space stations Centripetal Force Real Cause objects to move in a curved path Vector, directed towards center of curve (circle)