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Questions tagged [torque]

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

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1answer
20 views

Torque on dipole in a non-uniform electric field [duplicate]

What happens when an electric dipole is kept in a nonuniform electric field?
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0answers
22 views

Calculating what angular velocity a object has after one second [on hold]

So, I'm working on a 2D car game, and I need to know what angular velocity a object has after one second, if you can, please include deltaTime into the calculation. I've got the following variables: ...
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3answers
2k views

Why is torque sometimes reported in kg m, instead of the usual N m?

On various websites I see torque expressed as $\rm kg\: m$, but I was always thought that torque is $\rm N\:m$ or $\rm kg\: m^2/s^2$. These are clearly not the same, so why are they called the same, ...
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1answer
27 views

Translatory motion of a rod

For the translatory motion of a rod, shouldn't the torque about every point of the rod be zero? There is no rotation about any point right?
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2answers
62 views

Moment of Inertia of Infinite small rods! [closed]

Say we have a symmetrical and homogenous rod with mass $M$ and length $L$ and a rotating axis in the middle of the rod, dividing it into two halves. Its moment of inert is $$I_{cm}=\frac{M{L^2}}{12}$$ ...
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3answers
97 views

The direction of torque is so confusing [duplicate]

When I was studying cross and dot products, I learned that the cross product of two vectors A and B is perpendicular to both A and B. But my mind is unable to understand that. Since both A and B are ...
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1answer
15 views

Can't Determine the direction of rotation of a coil

Speaking of coils and torque here, So I have a coil and after I did fleming's right hand rule to get the direction of the torque (let it be the positive x-axis unit vector î can't remember it ...
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2answers
32 views

Clarify Torque and static friction [duplicate]

I came to this problem and solved it but I don't fully understand how this works. The problem is: A 200lb man climbs to the top of a 20ft ladder that is leaning against a smooth wall at an angle ...
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0answers
36 views

Mass is ignored in vector product of r(vector) and f(vector), why?

In this solution in the book, the mass is ignored after vector product of position vector and force vector. In both part a and b of the question it is the same. I was wondering what might be the ...
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1answer
29 views

How can I find the power given only the torque?

I have a system where I am trying to find the power generated by a DC electric generator. However, I am not very familiar with generators, so I am having difficulty determining the rotational velocity....
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1answer
39 views

What happens when you try to turn a gyroscope with high torque?

I apologize for my lack of basic understanding of gyro-physics, I tried looking up internet, but couldn't find any answer for this particular question. I have been told that if I apply torque to the ...
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0answers
39 views

Is angular momentum , energy? [duplicate]

is angular momentum energy? I mean why is the unit of torque N CROSS m and it is not considered energy but the unite of angular momentum is j.s?
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2answers
60 views

How to define signs for angular velocity, acceleration and torques?

I get confused how to define signs of angular velocity, acceleration and torques in the cases like the following. We have a disk with radius $r$ and center of mass at point $CM$ shifted $d$ from the ...
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1answer
30 views

In case of torque on sliding block on horizontal surface, why $y$ component of $\vec{r}$ is taken negative?

I've attached the picture above. In case of the torque on a sliding block on horizontal surface why r component is taken negative.
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1answer
45 views

Magnetic effect of electric current [closed]

A rectangular coil of length 0.12 m and width 0.1 m having 50 turns of wire is suspended vertically in a uniform magnetic field of strength 0.2 Weber/m$^2$. The coil carries a current of 2 A. If the ...
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1answer
33 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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0answers
39 views

Rotor finds equilibrium in TWO positions, why and how?

I have a Mendocino motor, a toy with magnets, solar panels, and coils. Such a thing requires careful balancing (eg. with tiny bits of tape) to achieve sufficient balance that it will start rotating ...
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4answers
146 views

Why do doors turn?

I really think that I might be overthinking it but I was thinking about a door. When you try and open it with a force, it will produce a translational AND a rotational effect on the door. Any good ...
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2answers
58 views

Does torque provide rotation?

If a sphere is given a constant force along centre of mass, placed on a frictionless floor it does not undergo rotational motion as net torque about centre is zero. But why did we notice net torque ...
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2answers
27 views

Couple or torque

In the solution of Problem 527, over here, A homogeneous cylinder 3 m in diameter and weighing 30 kN is resting on two inclined planes as shown in Fig. P-527. If the angle of friction is 15° for ...
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1answer
43 views

Torque lesson in Physics

For the force on a current-carrying wire, Torque, was derived using the assumption that the cross-section area of the wire is constant along its length. Is this equation still valid if the cross-...
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1answer
21 views

Stability of a falling object

Suppose there is a falling object that has flaps around it providing resistance to the non-contact force of gravity. How would the vehicle theoretically not flip over? From my understanding, the ...
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0answers
26 views

Slipping of a rod -dynamics

A uniform rod of mass m is placed at right angles to a smooth plane of inclination $\alpha$ with one end in contact with it. The rod is then released. Find reaction of the plane when the ...
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1answer
89 views

The minimum diameter of a sphere such that a cone may balance on it [closed]

There is a solid sphere of diameter D, with a right circular cone placed on top of it. The cone has a height h and the diameter of the cone base is d, and d=h. Explain why the minimum value of D (...
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2answers
55 views

Torque equation about center of mass frame

Let say a uniform cylinder is rolling down an incline. Since the center of mass of the cylinder has non-zero acceleration, should it be considered as a non-inertial reference frame? I know that when ...
2
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5answers
103 views

Why is torque defined as $r × F$ and not $F × r$?

Is it merely due to popular convention or does it supply any special clarification regarding other physical quantities?
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1answer
46 views

Balanced Torques and centre of mass

Say we have a plank of wood that is placed on the edge of a cliff so that one end projects horizontally out over the edge. How would you go about finding the minimum mass that you could place on top ...
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2answers
65 views

Which way does a cylinder on a slab roll after the slab is removed?

An article by Tokieda[1] begins: I lay a cylinder on a sheet of paper. I pull the sheet from under the cylinder, briskly or gently. When the sheet is pulled out, which way will the cylinder roll?...
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0answers
36 views

How would I find the angular accelertion of a disk rolling up a ramp? [closed]

I need to find the angular acceleration of a hollow ball rolling (without slipping) on a ramp, given the angle of the ramp theta, the mass and radius of the ball, and gravity and other physical ...
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1answer
30 views

Force required for Angular Accleration

Suppose I have 4' x 4' piece of wood. Its mass is 150kg evenly distributed. I drill a hole right at a corner and place rod through the hole to create a rotational axis. I apply a tangental force at ...
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2answers
40 views

Does mass affect how likely an object is to topple over?

I was at work recently pulling around some pallets when I had a thought. I wanted to know if the mass of the pallet had any influence on how likely it is for the pallet to topple over when going ...
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1answer
50 views

Why is it easier to put one's arm on table for lifting a box?

Why is it easier to put your elbow on the table to lift a box compared to just lifting it, hand in the air? Is it like some kind of torque or fulcrum and lever?
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1answer
70 views

Using Euler equations to solve for torque

I am trying to solve the torque needed to rotate a rectangular plate of sides $a$ and $b$, about a diagonal with constant angular velocity $\omega$. Euler equations are given by, $$ I_1\dot{\omega}...
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0answers
31 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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1answer
33 views

A rod with a ball attached is balanced?

An object is made by hanging a ball of mass $M$ from one end of a plank having the same mass and length $L$. The object is then pivoted at a point a distance $L/4$ from the end of the plank ...
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1answer
67 views

Rod that is toppling over

A rod is about to fall over. If $N=mg$, then there is no resultant vertical force acting on the object. So how is the object able to fall over? Intuitively I understand why it would fall over but ...
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1answer
36 views

Torque applied off the center of mass [duplicate]

I am trying to solve a problem involving a motor attached to an object. The motor is below the centre of gravity. When the motor is running it will apply a torque off axis to the object. What will ...
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1answer
57 views

Perpendicular weight force on an object that is tipping over [closed]

I'm currently working on a problem I can't seem to find an answer to. I have an object that is hanging over a cliff. This object is exactly 12m in length, and it starts off in equilibrium (6m over the ...
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2answers
36 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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3answers
82 views

Torque on a shelf

Say I have a shelf anchored to the wall (how it's anchored doesn't matter here I think), with a mass (m) taking up most of the space on the shelf: Say the shelf is x meters long, and the mass is y ...
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1answer
44 views

Normal Force on an object hanging over a cliff [closed]

this is the problem I'm having: Imagine I have an object with mass m, also with equal distribution of the mass. This object is portruding over a cliff, with some fraction of it being suspended over ...
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2answers
83 views

How to calculate the weight of a TV, mounted on a different type of brackets and positioned at different swirling angles? [closed]

The problem: So basically I want to calculate the weight/pressure of TV that I want to mount on my wall so I can on my own later on find the right anchors, right fittings, and TBH I am interested in ...
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1answer
32 views

Does the centre of mass of a circular object such as a cylinder or sphere rotate? [duplicate]

Say I pushed a cylinder to roll on a flat surface with velocity v, the point at contact with the floor will have zero velocity in order for the cylinder to not slip - which implies the point at ...
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3answers
48 views

Why does the force of a torque applied on a cylinder of mass $m$ at an arbitrary point equal to $F=ma$ circumference?

For the question I attached I can't seem to understand one part of it and my friend and teacher can't seem to explain it too. I've included the solution with my understanding of what's happening. The ...
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0answers
78 views

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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2answers
63 views

Why are tail rotors in helicopters vertical?

I guess spinning in perpendicular direction to main rotor is better in counteracting the torque but what's the mechanism at work?
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0answers
42 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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1answer
74 views

Proof of the Law of the Lever

Is there an accepted proof of the Law of the Lever? I know of several attempted proofs, such as Archimedes's, but these either are incomplete or do not transfer to the setting of Newton's Laws. (It ...
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0answers
28 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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1answer
60 views

What do we mean, concretely, by the unit $\rm N\:m$ (newton $\cdot$ meter)? [duplicate]

What do we mean, concretely, by the unit $\rm N\:m$ (newton $\cdot$ meter)? For example, $1 \:\rm m/s$ mean that each second, we make one meter. Also, $1\:\rm m/s^2$ mean that each second the speed ...