Ball in Horizontal Circle (Rotational Kinematics)

[PrideofPhilly]

Homework Statement

A ball at the end of a string of length 0.75 m rotates at a constant speed in a horizontal circle. It make 3 rev/s.

What is the period of the ball's motion?

What is the ball's angular velocity?

Homework Equations

w = delta theta/delta t

theta = 2*pi*r/r = 2*pi rad

The Attempt at a Solution

For period (in seconds):

(3 rev/1s)*(2*pi rad/1 rev) = 6*pi rad/s

(2*pi rad/1 rev)(1 s/6*pi rad) = 1/3 seconds

I don't know where to go from here? Did I find the period in the correct manner?

 

[LowlyPion]

Your period is OK.

More simply it is 3 revs in 1 sec, so ...1 rev in 1/3 sec.

 

[nlightner]

For angular velocity (in radians per second):

w = (2*pi rad)/(1/3 s) = 6*pi rad/s

Yes, you have correctly found the period and angular velocity of the ball's motion. The period is the time it takes for the ball to complete one full revolution, which in this case is 1/3 seconds. The angular velocity is the rate at which the ball is rotating, which is 6*pi radians per second.