# AP Physics Chapter 3 Study Guide

## Vectors and Motion in Two Dimensions

Vectors

Motion in Two Dimensions: Circular Motion

Period (T)- The period is the duration of one cycle in a repeating event.

Frequency - Frequency is the number of occurrences of a repeating event per unit time.

Angular Position

Arc Length - The length of an arc, or a section of a circle's perimeter.

Radians - A unit of angular measurement in which the arc length it cuts out of a circle is equal to the radius of the circle.

Example

An old fashioned LP record rotates at 33.33 rpm.
a. What is its frequency in rev/s?

b. What is its period, in seconds?

Acceleration in Circular Motion

Centripetal Acceleration - the acceleration directed towards the center of a circular path

Example

A peregrine falcon in a tight, circular turn can attain a centripetal acceleration 1.5 times the free-fall acceleration. If the falcon is flying at 20 m/s, what is the radius of the turn?

Example

A sports car is advertised to be able to "reach 60 mph in 5 seconds flat, corner at 0.85g, and stop from 70 mph in only 168 feet."

a. In which of those three situations is the magnitude of the car's accleration the largest? In which is it the smallest?

b. At 60 mph, what is the smallest turning radius that this car can navigate?