Centripetal Force
Fc = mv²/r — the net force that keeps an object moving in a circle
Centripetal Force (Fc) — the force directed toward the center of a circle that keeps an object moving in a uniform circular path
Fc and r Relationship
a is greatest from A to B. r is small.
A car moving in a circle is always turning in the same direction.
Go Nittany Lions!! 
Identify the Fc and v. What is the relationship between Fc and v?
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Cut the Rope
LINK — Author: Barb Newitt
D. Centripetal Force
(Fc) — force directed toward center of circle which keeps an object moving in a uniform circular path
AP Physics, p. 130 — problems 8, 11
Ex: Finding the Radius
A 5.0 kg object moves in a circle at a constant speed of 10. m/s.
Find: the radius of the object's circular path if the object's centripetal force is 1000. N.
E. Changing Centripetal Force
How Fc responds to changes in mass, radius, and velocity
1. Fc and Mass?
Put your mouse over each variable above
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Direct Relationship
(Both variables on top)
| Mass | Fc |
|---|---|
| x 2 | x 2 |
| x 3 | x 3 |
| x 4 | x 4 |
| x 1/2 | x 1/2 |
| x 1/4 | x 1/4 |
2. Fc & Radius?
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Inverse Relationship
(One variable on top, other on bottom)
| Fc | r |
|---|---|
| x 1/2 | x 2 |
| x 1/3 | x 3 |
| x 1/4 | x 4 |
| x 2 | x 1/2 |
| x 4 | x 1/4 |
3. Fc & Velocity?
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| V | Fc |
|---|---|
| x 2 | x 4 |
| x 3 | x 9 |
| x 4 | x 16 |
| x 1/2 | x 1/4 |
| x 1/4 | x 1/16 |
2 Step Challenge
A toy car moves in a circular track of radius 5.00 m in 10.0 seconds.
Find: the car's centripetal acceleration.
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Hammer Throw
Teaching from Space: Centripetal Force
This media asset is adapted from video provided by NASA's Teaching From Space program.
Produced by WNET.org
http://www.teachersdomain.org/resource/npe11.sci.phys.maf.centripetal/
