Calculating Angular Velocity: Motor at 60rpm Comes to Rest in 10 Revolutions

Join the discussion
Registration is free. Start your own thread to ask a follow-up.
Sign up Log in
1 reply · 1K views
pratz
Messages
1
Reaction score
0
A motor rotating at 60rpm comes to rest in 10 revolutions with its angular velocity decreasing linearly with angular displacement.Determine it angular velocity as a function of time and determine angular velocity w at t=3 sec..


I need help with this problem...Please someone help...I can't do anything in rotational mechanics:(
 
Physics news on Phys.org

Discussion

Hi Pratz, welcome to PF!

To get you started, you know the that the angular velocity is a linearly decreasing function of angular displacement, meaning that:

[tex]\omega(\theta) = \omega_0 - C\theta[/tex]​

You know what the inital angular velocity, [itex]\omega_0[/itex] is, because it is given in the problem. You can calculate the constant by noting that the angular velocity equals zero after ten revolutions: [itex]\omega(10 \textfm{rev}) = 0[/itex]. Remember to convert everything into radians. Now that you have this function [itex]\omega(\theta)[/itex], you can differentiate it with respect to theta. Can you think of a way of relating that to the time derivative of [itex]\omega[/itex]?