SOLUTION: PLEASE GIVE ME HELP A 12 cm diameter pulley runs at 240 rpm and runs an 8 cm diameter pulley. How fast does the 8 cm pulley rotate?

Algebra ->  Inverses -> SOLUTION: PLEASE GIVE ME HELP A 12 cm diameter pulley runs at 240 rpm and runs an 8 cm diameter pulley. How fast does the 8 cm pulley rotate?       Log On


   

Question 181147: PLEASE GIVE ME HELP
A 12 cm diameter pulley runs at 240 rpm and runs an 8 cm diameter pulley. How fast does the 8 cm pulley rotate?
Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!
there is an inverse relationship between pulleys I believe
:
so lets find the constant of variation k. let d be the diameter and r the speed
:
d(r)=k
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12(240)=k
:
k=2880 our constant of variation
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so for diameter of 8 what is the rotation speed
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8(r)=2880
:
r=360 rpm