Questions tagged [torque]

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

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Lagrangian of the Euler equations - why are Lin constraints required?

The following equation describes the motion of a rigid body rotation, such as a gyroscope: $$ \frac{d\textbf{L}}{dt} ={\bf{\tau}}= \textbf{r}\times m\textbf{g}= {\omega}\times \textbf{L}$$ where $...
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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 ...
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1answer
3k views

Neglecting friction on a pulley?

So, this is how the problem looks: Plus, the pulley is suspended on a cord at its center and hanging from the ceiling. You're given masses of the objects, mass of the pulley and it's radius. And ...
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382 views

Why do control moment gyroscopes exhibit “torque amplification”?

There are a number of articles that describe the benefits of using control moment gyroscopes (CMGs) over reaction wheels in inertial navigation applications. One of the primary benefits of using a CMG ...
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1answer
236 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 ...
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1answer
69 views

Why does the axis of rotation of a thrown football rotate downwards as it travels along its trajectory?

When a quarterback throws a pass, the football is angled upwards relative to the surface of the field, but progressively rotates downwards along it's path of travel. When initially released, I can't ...
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2answers
660 views

Static equilibrium question: Horizontal rod attached to a wall

I'm doing a problem on static equilibrium and I'm unclear whether a force exists or not. This is my force diagram: The setup is: a homogenous rod with a certain mass is attached to a vertical wall on ...
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1answer
268 views

Torque on rolling cylinder

Consider a rod with two equal forces acting parallel to the direction of velocity of a rolling rod, one at each end. When analysing problems involving torque, the choice of axis should not matter. ...
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367 views

Torque of a distributed load: Integrating with dF vs using resultant force

We have a rod that rotates around an fixed point A, which coincides with the end of the rod. The mass distribution along the rod is uniform. We know that the torque generated by the force field at ...
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157 views

What is the general proof that the torque acting on an irregular current carrying loop in an uniform magnetic field is only dependent on area?

How do you prove that the torque acting on an irregular current carrying loop in an uniform magnetic field in the plane of loop = $I \vec{A} \times \vec{B}$ Where, $ \vec{A}$ = Area vector of the ...
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75 views

The underlying chemical interactions behind torque

I did some searching around, and didn't find any previous topics that address torque in this specific way -- here goes: Say I just have a plain ol' piece of wood -- relatively long in one axis, so it ...
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72 views

The torque produced in the rotor blades of an axial flow turbine

I want to ask about the torque experienced by a axial flow turbine, and how the torque is related to the ange of attack, or pitch angle of the turbine blades. (I'm new to technical terms, please ...
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5answers
766 views

What is the effect of torque steering on a motorcycle with a long wheel base?

From experience, it appears motorcycles with a large wheelbase coupled with a long handlebar (say a modified Harley Ape Hangar) shows a noticeable tendency to veer to a side during acceleration vs a ...
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752 views

Maximum friction force for a wheel to be able to roll

The wheel with mass $M$ and radius $R$ below is free in space (it is not on the ground). A torque $\tau$ is applied to it through an engine. A horizontal force $F = \frac{\tau}{R}$ is also applied to ...
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777 views

Sum of energy in a free rotation with Algodoo software

I try to understand why Algodoo software (freeware) give an efficiency greater than unity. I tested several scenes and at each time I can look the software give energy, I don't say it's all the time ...
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3answers
196 views

How is it possible to calculate the moment of inertia?

I would like to calculate the angular acceleration of an object on which a force $F$ is applied at point $P$. The scene is 2D, and the complex object consists of many axis-aligned rectangles. I ...
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83 views

How to consider a moment of a force as a 2-form?

My major is mechanical engineering. Recently, I'm reading "The Geometry of Physics An Introduction (3ed)" by Theodore Frankel. On page lix in the section O.r, the author discussed the concept of ...
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27 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 ...
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33 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_{\...
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3answers
79 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 ...
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68 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) ...
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1answer
38 views

Mechanics, Torques in accelerated frames

Consider the following problem: My first attempt of a solution was taking moments about Point O and solve for variables by setting the final torque to zero. After consulting the text book and quoting ...
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59 views

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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2answers
39 views

Can anyone explain me how do I calculate torque?

For my gate automation project, I estimated the amount of force required (in order to estimate the torque) to pull my gate with a spring balance. The display on the spring balance read $2 \text{ kg}$. ...
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58 views

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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46 views

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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850 views

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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22 views

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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1answer
53 views

Plane rotation of a bar in a viscous fluid, computation of the torque

Assume a rigid, cylindrical bar which rotates around $\Omega$ (axis of a engine). The bar is immersed in a fluid of kinematic viscosity $\nu$ and has a plane motion. What is the torque applied to ...
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49 views

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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64 views

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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1answer
79 views

Finding the state space representation of a dynamic model with the force and angle as control inputs vector

I am trying to design a controller to control the angle of the force on my mobile rigid body. I some questions: I am not sure how to write the state space representation with the force, $F$ and angle,...
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65 views

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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39 views

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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1answer
50 views

Spinning ball gently lowered onto rough floor

Trying to reconcile the real world observation with first principles, here is a problem I came across. Consider a ball initially rotating with axis parallel to the floor lowered gently onto a rough ...
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2answers
405 views

Torque applied over center vs. off-center

I have a tool that loosens a bolt with the torque applied over the center of the bolt (box end wrench). I have a different tool that uses a socket which applies the torque (has the ratchet connection) ...
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1answer
287 views

Angular velocity - Gyroscope

I am currently researching the gyroscope on my own and i came across the concept of angular velocity. The torque ($T$) on a gyroscope is caused by $R\cdot F$, where the force i consider it to be ...
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2k views

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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2answers
259 views

How to spin a fidget spinner with maximum velocity?

Physics doesn't always come in the form of books. It also comes in the form of toys. So, I came across this fascinating toy that spins two minutes straight when given a spin. I got a chance to use ...
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1answer
94 views

If the bicep connects closely to the elbow joint, would the bicep need to exert more or less force to lift an object?

I would like to know whether a less or large amount of force is exerted by the bicep to lift and hold an object if the bicep is connected close to the elbow joint (fulcrum) than if the bicep is ...
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40 views

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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96 views

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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192 views

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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2answers
263 views

Find torque due to Lorentz force - Wrong result

Current I is coming from the Z axis and then it flows out uniformly towards the circumference of this disk. The disk has thickness t and Radius R. There is also a constant B field in the Z direction(...
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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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0answers
237 views

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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1answer
129 views

Effect of forces inside a sphere

What would be the effect of applying two parallel forces of the same value at opposite points of the equator inside a sphere? Common sense tells me that it wouldn't move, but it seems that it could ...
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2answers
265 views

The torque created using an oval chain ring

I have seen the explanation on "How bicycle gear works?" but this seem to be using a standard round chain ring. I would like to know if there is any difference when an oval chain ring is used. As I ...
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2answers
319 views

Determining the torque needed to rotate a spacecraft to a given rotation/quaternion

Which is the correct algorithm to determine the torque needed to rotate a spacecraft to a given quaternion ? I have a set of quaternions of a spacecraft and the time difference (delta T) between the ...
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1answer
82 views

Assistance in Francis Turbine Lab Experiment

Lately I did Francis Turbine Experiment at my institute. The objective was to find the efficiency of the turbine. Power input was found using flow rate and pressure gauge. Power output was found by ...