Rotating platform on top of another rotating platform

In summary: I think you could do it in a piece of code, but I'm not sure. In summary, Don is trying to estimate the readings from the accelerometers on the purple platforms after the platforms have been spun by the centrifuge and the Lazy Susan. He is not sure if the accelerometers would read the addition of the centripetal accelerations or not.
  • #1
The Don
11
1

Homework Statement


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.

Homework Equations


a_c = R*w^2

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!

upload_2015-12-3_12-27-28.png
 
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  • #2
Hi Don, :welcome:

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
The relationship between the two axes of rotation is unclear. Are they the same? Parallel? Orthogonal?
 
  • #4
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.

upload_2015-12-3_13-14-58.png
 
  • #5
BvU said:
Hi Don, :welcome:

You sure this is the right picture? Where is A? B? Rotation axes? accelerometer postions? And which (x, y, z?) acceleration do they ,measure ?
Sorry please see my latest post in the thread
 
  • #6
haruspex said:
The relationship between the two axes of rotation is unclear. Are they the same? Parallel? Orthogonal?
Yes, sorry for that. Please see latest post on the thread
 
  • #7
Ok. First you don't mean centripetal velocity. That would mean the same as radial velocity (if it means anything.). The term here is angular velocity.
Accelerations are vectors, so can be added. Find tha acceleration of the Lazy Susan relative to the main axis, then add the acceleration of the accelerometer relative to the Lazy Susan axis. That's nontrivial since the second varies as the Lazy Susan rotates around the main axis, so you need to include variables representing the instantaneous position of the LS.
 

1. How do the two rotating platforms interact with each other?

The two rotating platforms interact through friction and torque. As one platform rotates, it applies a force to the other platform, causing it to rotate as well. The direction and speed of rotation of the top platform will depend on the direction and speed of rotation of the bottom platform.

2. What is the purpose of having a rotating platform on top of another rotating platform?

The purpose of this setup is to create a more complex and dynamic system for studying the effects of rotation and its interaction with other forces. It can also be used for practical applications such as simulating the movement of a planetary system or testing the stability of a structure under rotational forces.

3. How is the rotation of each platform controlled?

The rotation of each platform can be controlled independently through the use of motors or other mechanical devices. This allows for precise manipulation of the speed and direction of rotation for each platform.

4. What factors affect the stability of the rotating platform on top of another rotating platform?

The stability of the setup can be affected by various factors such as the speed and direction of rotation, the weight and distribution of weight on each platform, and the friction between the two platforms. Other external factors such as air resistance and vibrations can also impact the stability of the system.

5. Are there any real-world applications for a rotating platform on top of another rotating platform?

Yes, this setup can be used for practical applications in various fields such as engineering, physics, and aerospace. For example, it can be used to study the effects of rotational forces on structures, simulate the movement of a planetary system, or test the stability of a rotating machinery.

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