Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [torque]

The tendency of a force to rotate an object about an arbitrary axis.

0
votes
2answers
42 views

What is the physics behind a pirouette?

Around last week, I watched a ballet production at the Melbourne Arts Centre, and boy was I amazed! These people dressed up in costumes were spinning on their toes in all kinds of ways, and I was ...
0
votes
1answer
46 views

Physical intuition behind torque converter

A torque converter (also here) is a device used in some cars. It uses several "fans" coupled through a liquid (transmission fluid) in order to perform the function of a clutch, but more importantly it ...
2
votes
3answers
86 views

Why cars have transmission gears?

Cars need transmission to efficiently vary the speed of the wheels and this due to the fact that the internal combustion engines have a very limited torque band. What I don't understand is why ...
0
votes
0answers
11 views

Magnitude of moment in 3d space

What's the magnitude of moment about O, if the vectors F, r1 and r2 all lie in the z-y plane? I know the magnitude of the moment is the cross product of force and the perpendicular distance from the ...
0
votes
0answers
36 views

How is the rotation of a ferromagnetic bullet affected by a coilgun?

I've been asked a question that I'm unable to answer. It's about a coilgun, and even if it could probably be expressed in simpler terms, I'll ask it in its entirety just in case I make mistakes while ...
2
votes
1answer
37 views

Friction in pulleys

The moment equation of a pulley with a rope applying tension on both sides is as follows: $$I\alpha = f + T_1R - T_2R$$ ( $I$ - moment of inertia; $\alpha$ - angular acceleration; $f$ - friction ...
1
vote
0answers
22 views

Why does the parallel axis theorem apply in this case?

Next, the wheel is flipped over, so the angular momentum of the wheel is now negative. Obviously, the person must start rotating counterclockwise to conserve angular momentum. Since the person is ...
2
votes
2answers
74 views

Is the parallel axis theorem valid for non-rigid bodies?

For some context, consider an idealized situation with a person, rigidly attached to the shaft of a bicycle wheel that can spin. sitting on a chair that can rotate. All bearings are frictionless. ...
3
votes
1answer
50 views

Is normal reaction a non-central force?

For an object of mass m to topple on a rough inclined plane, we consider the torques due to forces acting on it as shown in this figure: In the figure, we can see that forces along y-axis are ...
0
votes
1answer
23 views

How to find the acceleration of a spool pulled by a force and its work?

I need some help with this problem: A spool with thread wound on it, of mass $m$, rests on a rough horizontal surface. Its moment of inertia relative to its own axis is equal to $I= \gamma mR^2$ ...
0
votes
2answers
53 views

Off-axis torque

If one adds pure torque to a disc rotating about a fixed axis in such a way that the application of the torque is off the axis of rotation with the torque vector parallel to the axis of rotation, does ...
2
votes
3answers
73 views

Can a tilted wheel roll straight?

The common explanation of why a wheel that is falling to one side will turn towards that side to balance itself is gyroscopic precession, i.e. the torque produced by the falling of the wheel plus the ...
0
votes
2answers
51 views

Torque Equation [closed]

There are two torque equations. and I'm confused about when to use which one given a certain scenario.
0
votes
0answers
21 views

Torque Required To Make Object Circle

Say an object is going a constant velocity in the direction of A-B, with respect to its orientation. I'm wondering how you calculate the torque required to always keep point B at the edge of the ...
0
votes
2answers
70 views

Torque in a rubber band

So I have a bottle that moves with a propeller powered by a rubber band which when you twist the rubber band around and around, the bottle moves. I was wondering how torque plays in this. Is it that ...
1
vote
1answer
42 views

Work from string wrapped around cylinder [closed]

A cylinder, on a level surface angularly accelerates as a string wrapped around is put under tension. Because this string causes the cylinder to roll without slipping, the tension force cannot to any ...
0
votes
3answers
62 views

Bending moment in a cantilever beam

If I have a cantilever beam of length L fixed at the left end to a wall and I hang a weight W from it's right free end then why should the bending moment at a point x units to right of the wall be W(L-...
1
vote
0answers
32 views

Extending general relativity with torque based on quasimetrics

If torque is allowed to exist in the space part of the stress energy tensor $T_{\mu\nu}$ in the Einstein field equations $$ R_{\mu\nu}-\frac12 g_{\mu\nu} R = 8\pi T_{\mu\nu} $$ it would lead to $T_{\...
0
votes
0answers
27 views

Torque require to rotate a shaft

I have a solid cylinder (shaft) that I want to rotate around its axis. The cylinder is supported by two bearings at its ends. No other loads than the weight are applied to the cylinder. My question is;...
1
vote
3answers
74 views

Normal reactions with moments

A uniform ladder, $AB$, is leaning against a smooth vertical wall on rough horizontal ground at an angle of $70°$ to the horizontal. The ladder has length $8\ \rm m$, and is held in equilibrium by a ...
0
votes
0answers
36 views

Torque from Newton’s Laws

Is is possible to predict the motion of rigid bodies only in terms of Newton’s laws of motion without torque (for example by using the system of particles model)? For instance, if there was a rod of ...
0
votes
0answers
23 views

Counter Torque in Electric Generator

I am going to use some sort of “dynamo” or electric generator component to generate electricity from the flowing drilling fluid. However, the effect of the magnet rotating within an electrical coil ...
1
vote
0answers
67 views

Angular Impulse equations for rotational dynamics

Consider a 3d rigid body at rest initially, assuming no net external forces acting on it. It is set in perpetual rotation along one of its principal axis. Now an angular impulse (which is a vector) ...
-1
votes
1answer
51 views

Torque on a wire loop

I know how to find the magnetic dipole and solved it to be (10A)(0.005 m^2) = 0.05 in the -z direction. However, the next part of the question asks to find the magnitude and direction of the torque ...
0
votes
1answer
19 views

Gravitational Potential Energy between points on a disk

So if I wanted to calculate the potential energy between two points on a disk, would I just use the formula for Gravitational Potential energy? if so, what would be the mass? Would I use some form of ...
0
votes
2answers
141 views

Why does the gyroscope not move upwards?

I have been watching a lot of videos on gyroscopes. Everything I see says there are two steps in gyro precession: Gravity pulls down imparting a torque The gyroscope moves forward It seems to me ...
0
votes
0answers
17 views

Angular Velocity of a wake

I am trying to use Blade Element Momentum Theory to run some power calculations for a turbine I built, however, I'm having trouble with one value in particular. I derived the following equation for ...
0
votes
0answers
23 views

Query about angular momentum and torque

This question came from studying Rutherford scattering. As you can see in the diagram below, there is an alpha particle moving past a heavy nuclei and being deflected. In the following analysis of ...
0
votes
1answer
44 views

Torque Generated by Magnetic Field [closed]

This is the solution that was given: I'm extremely confused how the solution is getting a magnetic field in the +y direction. I do the right hand rule and I'm getting a B into the board ...
3
votes
0answers
36 views

Torque contacts

Does anyone know the answer? Or is it rocket science or unsolvable? I experienced yesterday that when the slotted screw driver head was exact fit to the slotted screw, it was easier to turn the ...
0
votes
0answers
35 views

Finding force exerted on a turbine blade by water flow

I am trying to find the maximum theoretical rotational power of a turbine from the following quantities: $\omega$, $r$, $\gamma$, $I$, and $t$. This is in an experimental setting, not an assignment,...
0
votes
0answers
19 views

Finding force from torque equation

I have read an article on electrostatics textbook that, $$\vec {F}= \nabla {\vec {\tau} }$$ Such as,the toraue equation on a magnetic dipole is $$ \vec\tau={\frac{{\mu}_0 m^2}{2\pi z^3} }\hat{z} $$ ...
0
votes
0answers
30 views

How do I draw a diagram of the forces that create the “barndoor effect” (unbalanced torque) in rock climbing?

I have been asked to use a diagram that illustrates when a flag in rock climbing is necessary. I have no idea how to draw the forces involved in torque.
0
votes
1answer
70 views

Newton's third law for rotating systems [closed]

As often happens for the rotational world, the Newton's law can be restated in terms of angles, moment of inertia and torques replacing displacements, masses and forces (this is one source among ...
-1
votes
3answers
46 views

Why the angular velocity in DC MOTORS = 0 when torque is maximum?

Why the angular velocity in DC MOTORS = 0. when the torque is maximum. is it supposed to be maximum with angular velocity and torque in the same time!
2
votes
0answers
79 views

Pushing Two Balls Into One Another [closed]

Say for instance you have two tennis balls. Placing one on the table, hold the other in your hand and have it touch somewhere between the side and top of the other tennis ball. Now, when you start to ...
1
vote
3answers
55 views

How can Torque act on an electric dipole if an electric dipole is not a rigid body?

According to my knowledge of physics, torque can only exist on a rigid body and an electric dipole is defined as a "system of charges" (equal in magnitude, opposite in sign) separated by an ...
0
votes
1answer
62 views

Is it possible to show that calculating the torque using the center of gravity results from an integral?

We assume that the object's density is the same everywhere, and that indeed has a perfectly rectangular shape. We also assume that its volume is continuous and dont work with particles here. To ...
0
votes
1answer
24 views

Deriving the equality between the external torque and the rate of change of angular momentum, for a system of particles

I've started working through Analytical Mechanics for Relativity and Quantum Mechanics by Oliver Johns and I'm stuck on deriving a formula. In the section titled "Change of Angular Momentum", Johns ...
0
votes
1answer
26 views

Pure rolling of cylinder with arbitrary inertia

I'm having trouble understanding how pure rolling is possible for cylinders with arbitrary inertia and arbitrary torques applied to them, because it seems that the reaction force doesn't necessarily ...
0
votes
2answers
39 views

Rolling w/out rotation Yo-Yo (torque)

given a Yo-Yo that is rolling on the floor without slipping: why is the total torque equals to T*r+F_friction*R=I*w rather then -Tr-F_frictionR=I*w ive set the ...
-1
votes
1answer
41 views

Resultant force from two lever arms held together at a fixed angle, weight hung on one arm

Trying to determine the resultant force F with the setup pictured below, given that L1, L2, and theta can vary. Not sure how to translate the torque applied by the weight to the force at L1. Thanks in ...
0
votes
1answer
39 views

What is the force on a dipole in a uniform electric field?

For an electric dipole of dipole moment $\vec{p}$ placed in an electric field $\vec{E}$ experiences a force given by $$\vec{F}=-\nabla U=-\nabla(\vec{p}\cdot\vec{E})=(\vec{p}\cdot\nabla)\vec{E}.$$ So $...
0
votes
1answer
48 views

Torque and angular acceleration , moments , counterweight

As mentioned before i am from a mechanical engineering background trying to design a product using counterweight. I was thrown into confusion regarding torque and moment even after doing my own ...
0
votes
0answers
21 views

Sine or cosine component of force on current carrying coil in a magnetic field

For calculating torque on a current carrying loop in a magnetic field, restoring torque that is, we use the $\tau=\vec{m} \times \vec{B}$ where $\vec{m}$ is the magnetic moment and $\vec{B}$ is the ...
0
votes
0answers
32 views

Forces on a Rotating Rigid Body

This question has been puzzling me for some days now and I thought I might ask you guys for some help. Say that we have a rigid body (like a rod) that is in a vacuum in space. Furthermore, say that ...
0
votes
0answers
32 views

Torque/Cross Product [duplicate]

Ok! My question is, what is the physical meaning of the vector produced by a cross product? For instance, in torque, what does the cross product’s resultant vector mean? What does it tell me about ...
0
votes
0answers
30 views

calculate the shear stress from surface traction

The problem is that I am simulating a hollow cylinder under torsion and I would like to compute the shear stress for it. The output of the simulation is the shear surface tractions. See the figure ...
-1
votes
1answer
52 views

Moment of inertia and torque [closed]

Why there is different moment of inertia with respect to point P about which a rigid body is moving around a circle with some velocity and spinning about its own axis compared to the one which is just ...
2
votes
1answer
161 views

Difference between torque, moment and couple

I know the basics of them like Torque is force multiplied by the distance (from the point where there is no rotation like centre of gravity). Couple acts because of two equal and opposite forces ...