since it starts and stops at the same point.
ǻș = șfíși
ǻș = angular displacement
șf = final angular position
și = initial angular position
Units: radians (rad)
At 12:10, the initial angular
position of the minute hand is
ʌ/ 6. After 15 minutes have
passed, what is the minute
hand’s angular displacement?
9.3 - Angular velocity
Angular velocity: Angular displacement per unit
time.
In Concept 1, a ball attached to a string is shown moving counterclockwise around a
circle. Every four seconds, it completes one revolution of the circle. Its angular velocity
is the angular displacement 2 ʌ radians (one revolution) divided by four seconds, or ʌ/2
rad/s. The Greek letter Ȧ (omega) represents angular velocity.
As is the case with linear velocity, angular velocity can be discussed in terms of
average and instantaneous velocity. Average angular velocity equals the total angular
displacement divided by the elapsed time. This is shown in the first equation in Equation
Instantaneous angular velocity refers to the angular velocity at a precise moment in
time. It equals the limit of the average velocity as the increment of time approaches
zero. This is shown in the second equation in Equation 1.
Angular velocity
Angular displacement per unit time