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Homework Help: Two Rpm problems

  1. Jun 24, 2012 #1
    1. The problem statement, all variables and given/known data

    Q1) If 4,180rpm is 38% of the max rpm speed what is the max rpm speed?

    Q2)Determine the number of revolutions a gear completes in 30 seconds when
    the gear turns at 100 revolutions per min

    2. The attempt at a solution

    Q1) Alright for this part, I was pretty confuse when they asked for the max rpm speed and the given percentage. Do I have to convert the percentage to a decimal and then convert it to rads? What do they also mean by the maxrpm speed?
    If I'm not mistaken, rpm is a measure of frequency right? Does that mean f=4,180rpm? In other words do I just put it in the frequency formula or should I divide it by 2∏ then put it in the frequency formula? ω=2∏f But then again it can't be ω because they're asking for speed not velocity. I could use f=1/T but they didn't give me the time. ARGH! I'm so confused!

    Q2)Alright 1 revolution is equal to 60s or 2∏ right? (correct me if I'm wrong). So by using this formula, f=1/T making T=30s and well now I'm stuck

    Note:Q1 and Q2 are different problems/questions
  2. jcsd
  3. Jun 24, 2012 #2
    1) if 4180 = 38%, what is equal to 100%?

    2) T is not 30s, T is the time it takes for the gear to complete 1 rev.
  4. Jun 24, 2012 #3
    4180 = 38%
    110 = 1%
    11000 = 100%?

    Would that be correct?

    Alright so 1 rev is = 2∏ right? So, well, not sure what to do after that. I'm completely lost. Sorry about that :frown:

    Does the 2∏ have to be divided by 100 or something?
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