Unit 8: Circular MotionSpring 2015

Agenda 5/12/15Newton’s Law Warm-Up

GA Information

Intro: Circular MotionNotes: Circular MotionPractice: Circular Motion

Problems

Six Flags Trip InfoYou will all be on my bus heading

there

Late Bus people will be with me on Bus 3 coming home

Early Bus kids are with Adams Bus 2

Track on Thursday?

Circular MotionDefined by objects moving in

perfect circles.

Principles are very similar to linear motion.

Let’s see how they relate

Comparison of Linear and Circular

Linear:

t= time to travel distance

v = dist/ta = v/tF = m*ap = m * v

Circular:

T = time to go around the circle

v = 2πr/Ta = v2/r = 4π2R/T2 F = m * v2/r = m* 4π2R/T2 p = m* 2πr/T

Circular VocabularyCentripetal Force:

◦NET Force directed toward the center of the circle

◦The NET force that keeps something from pulling away from the center of the circle

Centripetal acceleration◦Net acceleration of the object moving in a

circular motionTangential Velocity:

◦Linear velocity of an object at any time in the rotation

Agenda 5/15/15

1. Six Flags Break Down

2. Finish Circular Notes◦ Example Problems

3. Work Time: Finish Packets◦ Due by end of double period

4. On your own: Six Flags Final Assessment

◦ Due by end of period Monday

ExamplesAn object moving in a circle

completes one revolution every 3.0 seconds. If the circle has a radius of .25m, what is the tangential velocity?

Ans: .524 m/s

ExampleA 2kg mass is swung in a circle.

The mass completes a revolution every 1.2 seconds. If the radius of the circle is 1.0m, what is the centripetal force acting on the mass?

Ans: 54.8 N