1. Do Now
A sock stuck to the side of a clothes dryer’s barrel has a centripetal acceleration of 28 m/s2. If the radius of the barrel is 27 centimeters, what is the tangential velocity of the sock?

2. SWBAT: Discover Centripetal Force and apply it to problems.

3. Homework!
Check over your homework with your partner(s) and compare answers.

4. Centripetal Force
What keeps the car in a circular path? Which direction is the force acting?
Based on our previous discussions of Net Force, what do you think the formula might be for centripetal force?

5. Notes!
Centripetal Force: The Net force that is directed towards the center of an objects circular path.
Fc = mvt2 r
This can also be written as Fc = acm

6. 360 Degree Swing
As you watch, think about what the centripetal force must over come to keep the swing in circular motion.
How could we calculate that force and the girls speed?

7. Example
How fast does Susie need to go if the chains are 2 meters long and she has a mass of 27 kg?

8. Example
A pilot is flying an 1110 kg plane in a circle with a radius of 118 meters. How fast does the plane need to be going to stay in the loop and in the air?

9. Don’t Get Sick!
You are riding a spinning amusement park ride with a radius of 11m. If the rides tangential speed is 15 m/s and you have a mass of 90 kg, what is the centripetal force of the ride?

10. Pat Kinch used a racing cycle to travel 75. 57 km/h
Pat Kinch used a racing cycle to travel km/h. Suppose Kinch moved at this speed around a circular track. If the combined mass of Kinch and the cycle was 92.0 kg and the average centripetal force was 12.8 N, what was the radius of the track?

11. Conceptual Example
When you are in a loop of a roller coaster, what direction does the centripetal force act? What causes this force?
What direction is the centripetal force acting when a car goes around a curve? What causes this force?

12. Homework!
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