How to calculate motion of object pushed by force?

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Discussion Overview

The discussion revolves around the calculation of motion for an object subjected to a force that does not act through its center of mass. Participants explore the implications of such a force on both translational and rotational motion, seeking to understand how to quantify these effects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that F=ma applies when the force acts through the center of mass, questioning how to calculate motion when it does not.
  • Another participant suggests that understanding angular velocity, angular acceleration, rotational moment of inertia, and torque is essential for addressing the problem.
  • A different participant emphasizes that a force applied at an angle creates torque, which is distinct from the force itself, and suggests learning about equilibrium in both rotational and translational contexts.
  • One participant proposes two statements for confirmation: (1) the center of mass still follows a trajectory similar to when the force is applied at the center, calculable by F=ma, and (2) the object will rotate around its center of mass, with a hypothesis that this rotation is akin to being locked at the center of mass.
  • A later reply confirms both statements as true, but does not provide further elaboration or formulas.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the specifics of calculating rotational motion and the effects of non-central forces. While some statements receive confirmation, no consensus on detailed calculations or methods is reached.

Contextual Notes

Participants indicate a lack of clarity on formulas for calculating rotation and the effects of torque, highlighting limitations in their understanding and the need for further exploration of these concepts.

lemd
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Hi

I know F=ma is applied when force pushes through object's center of mass. But in case force does not go through center of mass, how will the object react? I think object will rotate a little but don't know how to calculate things such as rotation and translation speed like the case with F=ma. I tried to google but can't find a simple generic answer.

Can someone show me how to calculate such things?

Thanks
 
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lemd said:
Hi

I know F=ma is applied when force pushes through object's center of mass. But in case force does not go through center of mass, how will the object react? I think object will rotate a little but don't know how to calculate things such as rotation and translation speed like the case with F=ma. I tried to google but can't find a simple generic answer.

Can someone show me how to calculate such things?

Thanks

When you have progressed a little further, you will learn about angular velocity, angular acceleration, rotational moment of inertia, and torque. This will give you what you want.
 
actuallyy a force exerted like that ( i mean in a particular angle or direction). is know as torque and is different from actual force! :D ...
i think it is clear if learn more about equilibruim both roataional and transilational ! :D ..
 
Thanks

I remember I learned things like that a long time ago. Problem is physics is not my profession and so English is not my language when I learned them. I just want some short answers because I already tried google.

So here are something I found but can't confirm they are true or not. When a random force applied:
1/ Center of mass of object still moves in a trajectory like in the the case the force is applied in center of mass and can be calculated by F=ma. Is it true?
2/ Object will rotate around center of mass. But I can't find a formula to calculate it. My guess is that object rotation is the same as when it is locked by a pivot at the center of mass. Is it true? If these two are true then I can calculate motion by a random force
 
lemd said:
Thanks

I remember I learned things like that a long time ago. Problem is physics is not my profession and so English is not my language when I learned them. I just want some short answers because I already tried google.

So here are something I found but can't confirm they are true or not. When a random force applied:
1/ Center of mass of object still moves in a trajectory like in the the case the force is applied in center of mass and can be calculated by F=ma. Is it true?
2/ Object will rotate around center of mass. But I can't find a formula to calculate it. My guess is that object rotation is the same as when it is locked by a pivot at the center of mass. Is it true? If these two are true then I can calculate motion by a random force
Yes and Yes.
 

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