Impact velocity after exiting circular motion

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Discussion Overview

The discussion revolves around determining the velocity of a mass after it departs from a rotating disk. The scenario involves a mass positioned in a drilling on the disk, which is subject to both centrifugal force and an additional force due to oil pressure. Participants explore the implications of these forces on the mass's velocity upon release.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes calculating the tangential velocity using the formula v_t=rw and suggests using F=ma to determine the acceleration from the force F_a.
  • Another participant questions whether the force F_a acts after the mass is released, suggesting that if it does not, the mass would hit the housing with its tangential speed at release.
  • A different participant argues that F_a may still partially act after release due to its origin from oil pressure, raising concerns about its effect on the mass's acceleration at the moment of release.
  • There is a discussion about the role of centrifugal force, with one participant stating that from an inertial frame, there is no centrifugal force.

Areas of Agreement / Disagreement

Participants express disagreement regarding the role of the force F_a after the mass is released and the implications of centrifugal force. There is no consensus on how these forces affect the mass's velocity upon release.

Contextual Notes

Participants have not fully resolved the assumptions regarding the effects of F_a and centrifugal force, and the discussion remains open to interpretation based on different frames of reference.

dogge76
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Hello,

i want to determine the velocity with which an object moves after it has departed a rotating disk. In my problem there is a disk rotating with the angular speed w. On this disk there is a drilling in which a mass m is positioned. In case the thread in the drilling fails i need to determine the velocity with which this mass hits the housing. During the rotation there is a force F_a additionally to the centrifugal force. My idea is to determine the tangential velocity with v_t=rw and with F=ma i can determine the acceleration due to the force F_a. Do i need to determine another accelerations or velocities. I am doing a rough calculation therefore the calculation doesn't need to consider all possible effects. I inserted a scetch of the problem. I would very welcome some help. thanks
 

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@dogge76 Welcome to this forum, sorry for weird response above. I don't have time to look carefully at the problem now, but I'm sure someone will. (Maybe next time post it in the "homework" section using the template offered there.)
 
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dogge76 said:
During the rotation there is a force F_a additionally to the centrifugal force.
Does F_a still act after the mass is released? If not, then the mass will hit the housing with the tangential speed it had on release (ignoring air resistance etc.). What might be relevant for the damage to the housing is the impact angle, which depends on the radii of disc and housing.
 
@Krylov thanks for the welcome. I don't mind what the other guy said. I don't have time for such folly.

@A.T. No F_a doesn't really act after the mass is released but i think it does partially. This force comes from an oil pressure which means that some force will still act after release. The impact angle isn't very interesting at this point. But i don't really understand why it will only hit with the tangential speed, what about the force F_a ? In the very first moment it will surely accelerate the mass , wouldn't it ? And doesn't the centrigual force contribute to some radial acceleration ? i have added a scetch. a_a means the acceleration due to the Force F_a . a_r comes from the rotation.
 

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dogge76 said:
No F_a doesn't really act after the mass is released but i think it does partially.
You have to make up your mind here.

dogge76 said:
And doesn't the centrigual force contribute to some radial acceleration ?.
If you analyse it from the inertial frame, there is no centrifugal force.
 
No F_a won't act after the mass is released
 

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