Linked Questions

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2answers
8k views

Derivation of Euler's equations for rigid body rotation [duplicate]

Sorry for using this image, but I thought this was the most convenient way of asking this question. Please zoom in. I do not understand from the line, "Now, in the body frame $T = (T_{x'}, T_{y'}, T_{...
2
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1answer
2k views

Calculating acceleration offset by Center of Gravity (C.G.) [duplicate]

I'm trying to calculate the acceleration an accelerometer would read NOT placed in the Center of Gravity of the object. Let's look at the figure below (or in link provided). The accelerometer was ...
1
vote
1answer
969 views

One force applied to one point of a rigid body: centre of mass and torque [duplicate]

Let us suppose that one force is applied to a point of a rigid body that is not acted upon by any other force. I think an example can approximatively be a rock in deep space, far from any relevant ...
2
votes
1answer
469 views

Newton-Euler equations in frame not centered at center of mass [duplicate]

I'm having trouble with a step in the derivation of the Newton-Euler equations for rigid body translation and rotation when the body frame is not centered at the center of gravity. The Newton-Euler ...
0
votes
1answer
174 views

Would equations for a spinning top be an (x,y,z) vector [duplicate]

I am following the equations on this page, and for torque it is $mgr\sin\theta$, but I am curious about $r$. I am working on a game and I want to correctly model the top, and am curious if $r$ should ...
0
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0answers
55 views

Force and Torque being applied off-center due to magnetic forces [duplicate]

Say that I have two magnetic dipoles, one of which is rigidly attached to a freely movable inflexible body at some point that is not at the body's center of mass, while the other is fixed in space. ...
16
votes
8answers
7k views

What is the proof that a force applied on a rigid body will cause it to rotate around its center of mass?

Say I have a rigid body in space. I've read that if I during some short time interval apply a force on the body at some point which is not in line with the center of mass, it would start rotating ...
7
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5answers
4k views

How to choose origin in rotational problems to calculate torque?

We know that $\text{Torque} = r \times F$ and $r$ is the position vector. But the position vector depends on the choice of the coordinate system and in turn on the choice of origin. So, where should ...
6
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2answers
6k views

Do objects rotate around the torque vector or its center?

If a sphere has a torque vector coming out of it at point A, would the sphere rotate about its center or the axis of the torque vector?
3
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4answers
1k views

Is there a rotational analog for Newton's laws of motion? [duplicate]

In context of rotational dynamics my textbooks interminably states that there always exists a rotational analog for every linear variable and they are related to one another through similar equation. (...
5
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4answers
4k views

Why does Torque exist?

Specifically, why does force increase with the moment arm? What about making a perpendicular force farther away from the axis of rotation increases it? How does the moment arm cause that?
5
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2answers
12k views

Angular momentum with respect to the centre of mass

I have been told [Warning: I leave this because it's what I asked and allows to understand the dialogues in the comments, but Azad, whom I thank, has pointed that the formula does not hold in general ...
3
votes
2answers
4k views

Force acting on a simple rigid body in space

So this is the question that's been bothering me: Say you have a simple rigid body in space that is at rest or traveling with only translational motion at a constant speed. Say that the body is ...
6
votes
3answers
3k views

How to find the center of rotation? (2D)

First off, I'm assuming that a free floating polygon doesn't always rotate around its center of mass unless the net force is zero (based on the points below). If this isn't correct please tell me. ...
2
votes
2answers
5k views

Connection between moment/torque and centre of gravity?

So I understand how moments work with regards to basic examples like pushing a door, in that the further you are away from the hinges of the door, the greater the moment, which is like a turning force....

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