Uniform Circular Motion • Object travels in a circular path at constant speed • Distance around the circle is its circumference ○ C=2πr=πd • Average speed formula from kinematics still applies ○ v ̅=d/t=2πr Frequency • Frequency is the number of revolutions or cycles which occur each second • Symbol is f • Units are 1/s, or Hertz (Hz) • f=(number of cycles)/second=(number of revolution)/second Period • Period is the time it takes for one complete revolution, or cycle. • Symbol is T • Unites are seconds (s) • T = time for 1 cycle = time for 1 revolution Frequency and Period • f=1/T • T=1/f Centripetal Acceleration • Is an object undergoing UCM accelerating? • Magnitude of Centripetal Acceleration ○ a_c=v^2/r Centripetal Force • If an object is traveling in a circle it is accelerating toward the center of the circle • For an object to accelerate, there must be a net force • We call this force a centripetal force (F_c) • F_c=(mv^2)/r
