http://www.ck12.org Chapter 5. Motion in Two Dimensions
Whereris the radius of the circle andTis the period (time required for one revolution).
This equation can be incorporated into the equation for centripetal acceleration as shown below.
ac=v
2
r =
(^2 πTr)^2
r =4 π^2 r
T^2Summary
- In order to keep an object traveling in a circular path, there must be an acceleration toward the center of the
circle. This acceleration is called centripetal acceleration. - The acceleration in the case of uniform circular motion changes the direction of the velocity but not its
magnitude. - Formulas for centripetal acceleration areac=v
2
r andac=
4 π^2 r
T^2.Practice
Questions
This video is a demonstration of centripetal force using balloons and trays of water. Use this resource to answer the
questions that follow.
https://www.youtube.com/watch?v=EX5DZ2MHlV4
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/60134- What does centripetal mean?
- What is uniform circular motion?
- Why is centripetal acceleration always towards the center?
Review
Questions
- An automobile rounds a curve of radius 50.0 m on a flat road at a speed of 14 m/s. What centripetal acceleration
is necessary to keep the car on the curve? - An object is swung in a horizontal circle on a length of string that is 0.93 m long. If the object goes around
once in 1.18 s, what is the centripetal acceleration?
- circular motion:A movement of an object along the circumference of a circle or rotation along a circular
path. - centripetal acceleration:The acceleration toward the center that keeps an object following a circular path.