1. Chapter 10 CIRCULAR MOTION
Centripetal Vs
Centrifugal

2. 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)

3. 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

4. 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

5. 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

6. 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)