There are two disks of uniform density that touch at one point. their masses are in a ratio of 1:9. how many revolutions does the smaller disk make as it makes one rotation around the big circle? (assume that the disks do not slip)(adsbygoogle = window.adsbygoogle || []).push({});

This is my try:

a is small circle

b is big circle

M(a)/R^2(a)=M(b)/R^2(b)

M(a)R^2(b)=M(b)R^2(a)

M(a)R^2(b)=9M(a)R^2(a)

R^2(b)=9R^2(a)

assume radius of a=1

R^2(b)=9

R(b)=3

Circumference of B

2(pi)(3)=6pi

Circumference of A

2(pi)(1)=2pi

number of rotations a makes around b

6pi/2pi=3

so three rotations.

the answer is four.

help.

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# Homework Help: Two circles and revolutions

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