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This tag is for questions regarding to torque, which is a measure of the increase in angular momentum over time.
1,775 questions
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I can't understand how the lever gives a gain in force and where it comes from
I can't understand how a lever gives a gain in force, where it comes from, and why an object moves at all.
To make it clearer, let's imagine that we have a very small lever consisting of 4 small ...
17
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2
answers
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Who makes most effort when two people of different heights lift a table?
There are two people lifting a table of length $l$. One is short the other one is tall. The table is solid so its center of mass is therefore at the center of the table. Since the two people are of ...
- 173
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About friction in Problem 1.14 from Morin's Classical Mechanics Problem book [closed]
The problem is as followed:
I wanna try to approach this problem using a mix of free-body diagram and torque balancing. But I think I mix up the forces somewhere. Here is my attempt at drawing the ...
2
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2
answers
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A question on the motion of a rod rotating about a hinge
Consider the following typical setup
Here we have rod hinged to a point. Say, i apply non zero forces $F_1$ and $F_2$ are distance $r_1$ and $r_2$ as shown such that $F_1r_1=F_2r_2$.
Now if i measure ...
- 261
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Moments of forces acting on a rigid body that is rotating
The lower end of a homogeneous rod of mass ?? m and length ?? is placed in a socket, while the upper end is connected to a fixed vertical axis by a light, inextensible string, such that the string ...
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2
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What is the direction of rolling resistance?
I would like to know the direction of rolling resistance between an object and a surface. From my research, rolling resistance causes a torque around the center of mass of the object, and since torque ...
- 1,595
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answer
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Derivation of the centre of mass for a rigid body
Suppose I have a rigid body and that the forces $\mathbf{F}_1,\ldots,\mathbf{F}_n$ act at the position vectors $\mathbf{p}_1,\ldots,\mathbf{p}_n$ on this body.
Then the torque about the point with ...
- 139
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Deadlift bar length and stability
My partner and I got into a debate about deadlift bar length and how she finds it less stable and more difficult to deadlift using a full length barbell with standard weight plates than with one of ...
- 69
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1
answer
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Loose pulley tension and forces
I have a quick conceptual question in the construction below when there is a loose pulley holding L.
Will the tension everywhere in the string be the same so that the right and left side will have the ...
- 71
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vote
3
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What is work done by torque?
In my textbook it's written
Work done is always calculated on the displacement of the body parallel or anti-parallel to the direction of the force.
And, according to the formula it is :
$$\mathbf{F ...
- 384
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Rotational Mechanics - Why does adding a fulcrum change the point of rotation?
In a perfectly static object (such as the one depicted below) with no rotation or translation of the COM the moment about any point is zero:
I could calculate the moment about any end or the centre, ...
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answer
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Is angular momentum only conserved about the centre of mass?
I was solving this problem.
And here's how I approached :
Initial Angular momentum of the system is : $mvr$ and the final angular momentum is $I \omega$ where
$$I = mR^2+mR^2 = 2mR^2$$
This gives, by ...
4
votes
2
answers
230
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Angular acceleration about different axes
Say you have a wheel floating in space with forces of equal magnitude acting upward at the COM and downward at the right edge. I have always been under the impression that no matter the inertial frame ...
- 69
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answers
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Rotation vectors for spheres in velocity vector field are additive
Apologies as I am quite unfamiliar with rotational physics. But I hope that some physicists here may be able to give me a satisfying and intuitive explanation.
Background/Motivation: I am from a pure ...
- 245
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What exactly does torque do? [closed]
Every textbook I read explained torque as just a product of force times the perpendicular distance between the axis of rotation and line of axis of force. However, I am finding it hard to understand ...
