1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Simple rotational mechanics

  1. Apr 20, 2010 #1
    1. The problem statement, all variables and given/known data
    If a CD makes 1500 revolutions in 5 minutes, what is the CD's average rotational speed (in units of rad/s)


    2. Relevant equations

    [tex]\omega = \frac{\Delta\theta}{\Delta t}[/tex]

    -or-

    [tex]\omega = \frac{2\pi}{\Delta t}[/tex]


    3. The attempt at a solution

    This problem seems a little too simple (and I didn't use the given equation), so I want to make sure I did it right:

    [tex](5min)(60s/min)=300 seconds in 5 minutes[/tex]

    [tex]\frac{1500rev}{300s}=5rev/s[/tex]
     
    Last edited: Apr 20, 2010
  2. jcsd
  3. Apr 20, 2010 #2
    You didn't answer the question; how many radians are there in one revolution?
     
  4. Apr 20, 2010 #3
    [tex]\frac{300s}{1500rev}=.2s/rev[/tex]

    [tex]\frac{2\pi}{.2}=31.4rad[/tex]
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook