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## Hot answers tagged torque

14

In mechanics no. Torque is not a fundamental quantity. it's only job is to describe where in space a force is acting through (the line of action). Torque just describes a force at a distance. Given a force $\boldsymbol{F}$ and a torque $\boldsymbol{\tau}$ you can tell that the force acts along a line in space with direction defined by $\boldsymbol{F}$, but ...

10

The original question is tagged "Newtonian mechanics", but the author also talks about "fundamental forces", so I assume it may be of some interest to point out some fundamental phenomena that are observable with classical macroscopic objects, but are, strictly speaking, beyond Newtonian mechanics. In quantum mechanics, angular momentum of a photon is ...

5

No, if one simply hangs or stands, the force on the lever arm does not change. As, torque stands for $F \times r$. Here, if the only affecting force is weight, then $F=mg$, (In case one tries to climb up the arm or jumps on it includes some extra forces.) and is directed straight down, as long as the lever arm is horizontal. If the person doesn't change his ...

5

To the extent that torque (or moment) is derived from force, then force is more "fundamental" than toque. However, torque is certainly more than just force with additional “baggage”. And it’s more than just about coordinate systems. Torque and force are not a matter of either or. Both are needed for the analysis of motion and equilibrium. Moment, which is ...

4

From a purely Newtonian mechanics perspective I would argue that force is more fundamental concept than torque. This is mainly because torques is, for lack of a better term, a property of forces. Also, the torque produced by a force depends on your subjective choice of which point you are calculating the torque about. This is all captured in the definition ...

4

Yes, the concepts of force and torque are equally fundamental. Noether's theorem states that each symmetry in a physical system corresponds to a conservation law. The symmetry under translation results in the conservation of momentum, of which force is the derivative (therefore the sum of all forces in a physical system is always 0). The symmetry under ...

2

Yes, they are equally fundamental because they are both "forces" in the same sense. The relationship between torque, angular momentum, and angles is identical to that between linear forces, linear momentum, and position. Take the equation $\mathbf{F} = m \mathbf{a}$. Properly, that equation is $\mathbf{F} = \frac{\mathrm{d} \mathbf{p}}{\mathrm{d} t}$. One ...

1

You can easily work in the non-inertial frame where cart is at rest. Then your reference point is not moving, and you just need to include an additional pseudoforce acting at the center the pendulum of $ma$ where $a$ is the acceleration of the system relative to the ground (similar to how we take the gravity force $mg$ to act at the center of a uniform body)....

1

In order to have a rotation, you have to have some force on it that doesn't act through the center of mass. Gravity is considered to act entirely on the center of mass and never creates a torque. The ramp can only supply a normal force at the point of contact (since it is frictionless). This force must act through the center of mass and can impart no ...

1

There is a slight difference due to the change in the lever arm between the hanging position indicated and a sitting position. the girl’s weight is applied to the very end of the see-saw plank; her center of mass will be directly below where she is holding the plank. When she’s sitting on the plank the effective lever arm will be shortened by something like ...

1

You will have both rotational and translational acceleration since there is a net force acting on the disc. Therefore you will have both angular and linear momentum. If you had two equal but opposite forces acting on opposite sides of the diameter of the disc (a force couple) then you would have pure rotation. Hope this helps

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