# Force Equilibrium Problem

Hello,

I am a first time poster and I need some help with a basic statics problem. I drew a free body diagram to help illustrate. An object with a mass 'M' is resting on a rotating disc that is spinning with constant velocity 'V'. The mass is continuously being pushed into a static wall due to the rotating disc beneath it. The mass is stationary because it is being stopped by the wall. Thus, the static wall forces the object to slide across the surface the disc as the disc rotates.

The question is, what is the reaction force of the wall? Given the mass of the object and the velocity of the disc, what else do I need to know in order to solve this problem? Friction force? If so, which way is it pointing? I was hoping someone can point me in the right direction. I have attached the image of the FBD in the thread. Let me know if you need any additional information.

Any help is much appreciated,

David

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SteamKing
Staff Emeritus
Homework Helper
Your diagram is rather unclear. Where is the center of rotation located?

"The mass is continuously being pushed into a static wall due to the rotating disc beneath it."

This may be true.

"The mass is stationary because it is being stopped by the wall."

This may be true.

"Thus, the static wall forces the object to slide across the surface the disc as the disc rotates."

How do you figure this conclusion? Are the wall and the object attracted magnetically? Are you sure that a more reasonable explanation might be possible?

If you want to calculate the reaction of the object, always remember that F = ma.

How would friction determine the reaction of the object on the stationary wall?