Find the size of Driving couple, if given the power?by alec433lawrid Tags: angluar velocity, power, torque 

#1
Mar912, 04:54 AM

P: 2

1. The problem statement, all variables and given/known data
Not really HW, just revision. A shaft rotating at 3000 revolutions per minute is transmitting power of 10000 watts. find the size of the driving couple. 2. Relevant equations Total wrk done by couple = 2.F.r.θ Work = Torque . θ ( angle of rotation ) Power = work done / time 3. The attempt at a solution 60 seconds = 3000 revolutions 1 second = ? Ans came to 50 Using ω = 2∏f resulted in ω = 100∏ Power = (Torque . θ)/t where θ/t = ω Subject of the formula gave me 9.54 as an answer. When it should be 32Nm What have I done wrong? 



#2
Mar912, 05:02 AM

Sci Advisor
HW Helper
Thanks
P: 26,167

hi alec433lawrid! welcome to pf!
how did you get 9.54 ? 



#3
Mar912, 05:14 AM

P: 2

Oh wow!, I am such a noob!
Sorry for wasting your time. I did have the correct answer. ie my reasoning was correct. My calculator skills on the other hand let me down :( I did 10000 / 100∏ when i should have done 10000 / (100 * ∏ ) It was a stupid mistake.... 


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