# Homework Help: Rotating platform on top of another rotating platform

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1. Dec 3, 2015

### The Don

1. The problem statement, all variables and given/known data
Have platform A that is being spun by a centrifuge with a radius R1 and centripetal velocity of w1. On top of platform A is a Lazy Susan (Platform B) that spins about a radius R2 with a centripetal velocity of w2. There are accelerometers placed on the the purple platform (see pic). Estimate what the accelerometer readings will be.

2. Relevant equations
a_c = R*w^2

3. The attempt at a solution
I'm thinking the accelerometers readings would be the centripetal acceleration. I'm able to get the centripetal acceleration of Platform A and Platform B separately however I'm not sure whether the accelerometers would read the addition of these a_c or not. Please help!

2. Dec 3, 2015

### BvU

Hi Don,

You sure this is the right picture? Where is A? B? Rotation axes? accelerometer postions? And which (x, y, z?) acceleration do they ,measure ?

3. Dec 3, 2015

### haruspex

The relationship between the two axes of rotation is unclear. Are they the same? Parallel? Orthogonal?

4. Dec 3, 2015

### The Don

Hi BvU,

Here is another picture showing the rotation Axis....Platform A is the gray box and Platform B is the blue platform in the pictures. R1 is the radius of the centrifuge's arm and R2 would be approximately the length/2 of Platform B.

5. Dec 3, 2015

6. Dec 3, 2015