# Questions tagged [torque]

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

153 questions
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### 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) ...
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### Does the hinge reaction do any work?

I was doing some questions in rotational mechanics and I am not able to understand the concept behind hinge reaction which acts on a rod suspended at a point. I am taking a simple example here. Let's ...
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### Gravitational attraction between a particle and a bar

I'm trying to solve this problem from the book "Fundamentals of Applied Dynamics" by R.A.Tenenbaum. I start it by trying to find the resultant gravitational force by the means of integration. d\...
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### How to calculate torque for a linear slide pulley?

I have a linear slide pulley system like in the picture (the string on the right will be attached to a spool, which is attached to a motor) and I'm trying to determine the right motor to buy to power ...
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### What causes this corkscrew-shaped object to rise up in a stream of water falling down?

A corkscrew-shaped object is floating in a tub of water. When water is poured into the tub from some height, the object starts rising up vertically in the stream of water. The water stream is falling ...
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### Static Equilibrium: cable sag considering equal pulling forces on extremities

When considering a cable with a non-negligible mass and an equal force pulling the cable at both extremities, how can one compute the mid-span sag or a sag function whilst accounting for this pulling ...
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### Torque on a quarter-wave plate… Where is the force? Where is the moment arm?

If you shine circularly polarized light (carrying angular momentum) through a quarter-wave plate, the light will emerge as linearly polarized light (carrying no angular momentum) from the other side. ...
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### Transverse speed of hamster in wheel as function of theta

i need help with conceptual understanding of how this system works. A small animal is running in a wheel with radius R, (and 0 mass). When the animal is at an angle $\theta = \alpha$ measured from ...
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### Calculus of torque to move a small vehicle

I have a to choose two DC motors in order to carry a vehicle. I assume that the mass of the whole vehicle (all components included) is 1Kg, the surface is flat and made of wood, the wheel coupled to ...
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### How to account for forces between connected bodies?

So lets say that I have a system which consists of two 1kg spheres (1 meter radius) which are connected by a massless rod which keeps the centers of the spheres at a fixed distance of, say 10 meters. ...
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### How to calculate theorectical engine max. torque from max. power and RPM?

I'm trying to come up with a formula to estimate an engine's maximum torque (and at which RPM) given other values and some assumptions. I'm approximating an engine's torque curve as 2 linear ...
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### Do couples act in current/ampere balances

I understand that the basic principle of a current balance is that mg=BIl when equilibrium is reached and thus B can be found. This means that torques must act when the mass is placed on the balance ...
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### Determining the mass of my car via m = F/a

I'd like to do something unconventional. I'd like to weigh my car by hitting the gas. I have an accelerometer in my phone (a). I'm trying to determine the force the car is exerting (against the road, ...
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### Equations of motion for a torqued spherical pendulum

I Want to simulate a spherical pendulum with a torquer on it, i.e. the angles of the pendulum change not only due to torque generated by gravity, but also by a torquer attached to the top of the ...
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### Rotating disc ('fidget spinner') off of its axis of rotation (while it is spinning)

A craze of 'fidget spinner' toys has broke out recently in my hometown. If you are unfamiliar, they are basically just discs with a fixed joint and ball bearing at the center so you can rotate them ...
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### Summation of Forces through a Lever Linkage

I'm trying to brush up on some of my force and torque stuff so I can do some modelling in software. My problem is, it's been a while and I'm unsure of how correct my work is. I have a system as ...
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### Compute taper joint resistance to slipping

In toolholding a standard method is to use a taper joint. The shank of the tool is tapered and fits into a socket in the spindle like this: Typically both the shank and the socket are made of ...
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### Torque of a wire tensioner dancing arm

I'm creating a wire tensioning sub-system for a coil winder, and I've decided to use a dancing arm to measure the tension in the wire as it is pulled off a supply reel, like so: As the tension in the ...
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### Would setting a magnetic base to the “off” position remove the torque from an external field?

A magnetic base is a permanent magnet mostly inside a ferromagnetic case. It can be rotated so that the field is either internally shunted through the ferromagnetic blocks, or so that the blocks are ...
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### flow rate measurement of a fluid

I had an experiment related to piping networks in my institute. In the experiment there was a device that was measuring flow rate based on rotations of a fan-like system. This created a doubt in my ...
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### Are these torques correct for a simple balancing/fulcrum experiment?

For my physics lab, they had us do a simple static equilibrium experiment where we rested a ruler on a fulcrum (at its center of mass) and then attached varying amounts of weight on either end at ...
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### Find the force and the torque so that the cylinder is in balance

At the cylinder of the picture there are static pressures from environment fluid of density $\rho$. If we neglect the atmospheric pressure, calculate how much force and how much torque is needed so ...
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### Where does the center of mass torque come from?

When calculating the torques about a pivot point, there is a torque that comes about if you aren't rotating about the center of mass- where does this torque physically come from? For instance, given a ...
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### Question about calculating the torque of a magnet in an additive field

I did an experiment in the lab today where I placed a magnet in between two coiled magnets, with one coiled magnet having its south side up and north side down and the other coiled magnet with the ...
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### Pressures in multiple hydraulic drive system circuits when driving common drive shaft

Assume that there are two 'idealised' and identical hydraulic drive system circuits each consisting of a connected positive displacement pump and hydraulic motor where both motors (from each ...
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### Rolling in 3D using Torque, Angular Momentum/Velocity

I'm stuggling to get a simulation working correctly. Below you can see what I am attempting to do. You can also view it here. Can you spot where I'm going wrong? (Calculated at start) 1) Inertia ...
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### How to measure the energy required to pedal an exercise bike

I have hacked a FitDesk exercise bike to output the RPM of the pedals and the position of the resistance control within its range of travel. I want to characterize the energy that is required to ...
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### Angular Momentum Conservation in Gravitational Interaction

thanks for any help. I'm trying to show that in a 2body problem, angular momentum is conserved given that $\dfrac{dp}{dt}=\dfrac{-GMm(rv)}{r³}$, where p is momentum, t time, G gravitational constant, ...
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### Two impulses on body

Suppose I have a physics simulation with a single body with three degrees of freedom (two axis and rotation). I have two impulses of equal magnitude in opposite directions. When applying these ...
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### Dose the gravitational force produces precession in the spinning top?

I'm new at classical mechanics but the text book says there is the torque in the spinning top which generated only by gravitation. It is hard to explain the situation, I've add the link. http://...
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### Torque, lever and mass

The Force used in a catapult is exerted near its axis. If we double the length of the arm of the catapult, but still use the same Force at the same point as before near the same axis, does the ...
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### Moment about axis with force applied at non-parallel line

I understand the process to solve the moment of a force at a given point applied about an axis. However, what if the force was instead applied to a second, non-parallel? Perhaps a physical example is ...
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### Can we add torques on different parts of body about a point and calculate total torque about that point?

Give proof also . I was doubtful as in a question . Torque due to a couple was calculated using adding torque of the couple due to different parts of the body .
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### Conceptual Question Regarding Torque and Acceleration of a system

I have a quick question regarding a system with a pulley, a cylinder on an incline, and a block hanging down vertically from the pulley, all connected with a tension cord. IF the pulley has mass, then ...
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### 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 ...
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### 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 ...