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Centripetal force 
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#1
Mar1412, 05:34 PM

P: 21

1. The problem statement, all variables and given/known data
Find the centripetal force required to rotate 6 kg object in a circle at a radius of 6m at one revolution per second. 2. Relevant equations C.F. = mv2/r [b]3. The attempt at a solution[/b Circumference=2 pi r=2*3.14*6=37.68 C.F. = 6*(37.68)2/6=1419.78 I just want to check whether my working is correct or not. 


#2
Mar1412, 06:15 PM

P: 614

that's about what I got too ^^



#3
Mar1412, 06:54 PM

P: 343

Looks like you wrote down
CF = m v^{2}/r but then you calculated the circumference, C = 2 π r and then you said, CF = r C^{2}/6 = C^{2} Why would you expect the centripetal force to be equal to the square of the circumference? It really is not. Try it again, starting with CF = m r ω^{2} and see how that turns out for you. You failed to get the time information into the problem. 


#4
Mar1512, 06:26 AM

P: 21

Centripetal force
so
CF = m r ω2 CF = 6*6*(37.68)2=51112??? 


#5
Mar1512, 06:33 AM

P: 66




#6
Mar1512, 07:52 AM

P: 21

now i am confused :C



#7
Mar1512, 08:19 AM

P: 66

However, to get it right with the second formula, you have to use the proper value for ω, which in this case is 2π/s. It would probably clear things up, if you would carry the units throughout your calculation and not just the numbers, that way you can always check if your result makes sense. 


#8
Mar1512, 08:21 AM

P: 12

I think your working is correct



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