Centripetal Acceleration Centripetal Force Circular Motion 2 Centripetal Acceleration Centripetal Force

Do Now Force Fg exists between two masses. What happens to Fg if you… Double both masses Double the radius Triple one mass, double the other, and decrease the radius by ½ r m1 m2 Fg

Practice- Circular Motion 1 B C A 0.32 s, 9.8 m/s, Yes- changing direction 5 s, 15.9 m 10 s, 0.3 m/s

Uniform Circular Motion Definition: An object that moves in a circular path at constant speed. Question: If an object undergoing UCM speed remains constant, does that mean that its velocity is constant?

Uniform Circular Motion Definition: An object that moves in a circular path at constant speed. Fill in the Blank: If there is a change in velocity, there must be an ______________.

petal- “Walking towards” Centripetal centri- “Center” petal- “Walking towards” V

Centripetal Acceleration An object moving in UCM undergoes a change in velocity. Therefore, that object is accelerating. a c = v 2 r V ac ac = centripetal acceleration v = tangential velocity r = radius of the circle or arc

Centripetal Acceleration An object moving in UCM undergoes a change in velocity. Therefore, that object is accelerating. a c = v 2 r = 4 π 2 r T 2 V ac ac = centripetal acceleration v = tangential velocity r = radius of the circle or arc

This force always acts towards the center of the circle. Centripetal Force The centripetal force is the net force that keeps an object moving in UCM. This force always acts towards the center of the circle. V Fc F c =m a c Fc = centripetal force m = mass ac = centripetal acceleration

This force always acts towards the center of the circle. Centripetal Force The centripetal force is the net force that keeps an object moving in UCM. This force always acts towards the center of the circle. V Fc F c =m a c = mv 2 r Fc= centripetal force m=mass ac= centripetal acceleration v= velocity of the object r= radius of the circle or arc

https://www.youtube.com/watch?v=KnHUAc20WEU

Question: Fc ac What are some examples of a centripetal force? V Remember: The centripetal force is the net force that keeps an object moving in UCM. This force always acts towards the center of the circle.

Types of Centripetal Forces Friction Tension Gravity Remember: The centripetal force is the net force that keeps an object moving in UCM. This force always acts towards the center of the circle.

Example 1 A 2000kg car moving at a constant speed of 25m/s takes a turn around a circle with a radius of 200m. What is the centripetal acceleration of the car? What is the net force acting on the car? What is the frictional force acting on the car?

Example 2 In an experiment, a 0.3kg rubber stopper is attached to one end of a string. A student whirls the stopper overhead in a horizontal circle with a radius of 0.5 meters. The stopper completes 20 revolutions in 15 seconds. What is the acceleration of the stopper? What is the tension in the string?

Circular Motion Lab

Extended Learning (optional) Centripetal vs. Centrifugal

Centripetal vs. Centrifugal Centripetal force is the “center-seeking” force that keeps an object moving in a circle. Centrifugal force is the “imaginary” outward “force” felt due to an object’s inertia as it moves in a circle. http://www.physicsclassroom.com/mmedia/circmot/wi.gif http://www.physicsclassroom.com/mmedia/circmot/cf.gif

https://www.youtube.com/watch?v=-LDxOSz80pI