# Questions tagged [torque]

This tag is for questions regarding to torque, which is a measure of the increase in angular momentum over time.

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### The forces acting on the tensegrity structure

Are these the only forces acting on the body. I assumed the COM to be somewhere there in between. since the tension in main string doesnt perfectly coincide with COM theres a small torque being ...
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### What is the physical significance of the cross product of curl of a vector field $v$ with another vector field $w$?

I think if curl of a vector field v corresponds to an applied rotation, it's cross product with a velocity vector field w (say) should give something analogous to the resulting torque. Am I close?
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### If the tidal bulge on the earth speeds the moon up, how does the moon move to a higher orbit?

I understand that the moon causes a tidal bulge on Earth, and this tidal bulge moves slightly ahead of the moon due to Earth's rotation. When reading about why the moon is moving away from the Earth, ...
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### Why more torque when force is applied more distant from the pivot in an atomic view? [duplicate]

Why more torque when force is applied more distant from the pivot? I want an intuitive atomic view. I don't want mathematical formula torque= force* distance. Thanks.
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### Equation of Torque

The magnitude of torque is defined as the product of the perpendicular (to the object) component of the force I apply and the distance between the axis of rotation and the point of application of the ...
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### Direction of the normal force [closed]

Suppose we have a bar with non-zero mass inside a hemispherical bucket fixed to the ground. Suppose, too, that there is friction between the bar and the inner spherical surface of the bucket. Part of ...
1 vote
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### Why is it possible to keep an object, say a book, horizontal while holding its corner?

When holding a book from its corner with two fingers in a pinched position, the fingers act as a sort of hinge, and the book is free to rotate about this corner only. The external forces acting on the ...
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### Like force, does the rotational effect of force/torque require some finite time to travel through a real body?

Let's say I am using a long wrench to unscrew a tight bolt because the formulas developed in rigid body statics states that the moment arm should be longer for minimal force application. But how long ...
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### Is there a way to explain torque and Euler's Laws of Motion from Newton's Laws

If I have a rigid rod and I apply a force $\vec F$ distance $r$ away from the centre of mass the torque on the rod is $\vec r \times \vec F$ from the centre of mass and the torque causes the rod to ...
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### Weight and rate of movement

Im limited on my physics knowledge and sometimes can't understand simple laws. When i have two 5kg objects on a "manual weight scale" then forces are equal and the scale stays in place. ...
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### How can Torque and Work have the same dimensions (both can be expressed in N.m because Joules = m.N = N.m) but they represent diffrent quantitie?

So torque and work are both distance times force but how can they be so different conceptually? I understand the torque is an outer product and is a vector while work is a dot product and is a scalar ...
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### How many components does the net force have on a rotating object?

I understand that there is the radial and tangential force components acting on a spinning object, but according to the attached image from my book, there is a third component F_1z that is ...
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### What are the physics behind the torque trick that uses a single match to hold a water bottle?

https://youtu.be/CO5YUrbFTig?si=6HBL6tsSZqS6EWkq I have seen a lot of videos about the same physics trick lately. How would I be able to do this trick myself and find out what forces are interacting ...
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### Convention or reality?

In case of a disc rotating about an axis perpendicular to its plane passing through its centre of mass, the torque vector points up or down depending upon direction of rotation. Is it just convention, ...
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### Confused with the effects of moment of inertia and torque

According to the definition of torque, if the distance from the pivot is large the force required to apply will be smaller to move with the specified angular velocity/acceleration. And we can ...
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### Torque of a lever with two fixed points at an acute angle

Is the torque at the yellow fixed point calculated using the perpendicular distance between the yellow fixed point and the red weight, or using the distance between the yellow fixed point and the blue ...
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### Can we model the pitch up of an aircraft due to sudden application of brakes while it is rolling down an inclined using angular impulse method? [closed]

Consider an aircraft parked on an inclined plane. Due to a mistake by the pilot the brakes were released, and the wheel chocks were missing. When the plane started to roll down, the pilot applied the ...
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Please explain Michael Seifert's answer here I think $x,y$ are distances but what is $d$? How did he get this formula? x cos ⁡ θ + d sin ⁡ θ Does this ...
1 vote
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### Normal reaction exerted by a rolling object

If we take a disc of mass M and radius R and assume that the disc is performing Combined rotational and translational motion on a frictionless flat surface. then if we take a point at the top of the ...
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### Why does torque increase with radius or distance from the centre?

Why is it that making a perpendicular force farther away from the axis of rotation increases the rate of change of angular momentum (hence, torque)?
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### Maximum Velocity of Car in Circular Motion Without Tipping?

We are tasked with finding the maximum velocity of a 4-wheeled vehicle undergoing circular motion without tipping (assuming that the force of gravity will act at the car's center of mass and the the ...
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### Why is the output torque less than the input force of 20N applied from a wrench having length of 0.8m?

A wrench is of length 0.8m, or any number below 1.0m, I am exerting a force of 20 Newtons on the point A (one end of the wrench), on point B there is a bolt (on other end). If I calculate the Torque ...
1 vote
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### Calculate rotation from net torque and inertia matrix

I am trying to grasp the concepts of forces applied to a rigid body resulting in a net change of the rotation of the object. This is not a home assignment and I read some resources on both the web and ...
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1 vote
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### Is Joule equivalent to Joule/radian? [duplicate]

The work a constant torque does when it moves a particle through an angel $\theta$ is given by $\tau \theta$. The work is measured in Joule, so the torque should be measured Joule/radian, but the ...
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### Equations for Torque Capacity and Bolt Clamping

I am doing research into how I can best approximate the torque capacity of several components bolted together in an assembly and specifically when a pattern of bolts is holding several parts together ...
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### Problem while calculing the bending torque of internal air pressure in a soft actuator

this is a question I cant resolve while looking a paper I needed for my undergraduate thesis. In this image (from Modeling of Soft Fiber-Reinforced Bending Actuators, Panagiotis Polygerinos et al.), ...
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### Can the brakes of a Semi-trailer truck overcome the torque of the engine? [closed]

On the average Semi-trailer truck, assuming an average load, can the engine overcome the brakes and continue spinning the wheels despite the operator applying the brakes fully? This would be assuming ...
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### Torque profile with fixed boundary condition

I am trying to find a simple treatment of elasticity theory of a scenario where I have a thin rod attached to a disc (radius $r_0$), and the disc is held fixed at its edge. Now I apply some torque to ...
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### Rotational Equilibrium With Forces acting on only two points

Imagine a rod that is held at angle to the vertical by some hook. The rod is in equilibrium. There would be three forces on this rod - Normal contact, Friction, and the weight of the rod. I struggle ...
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### Misconception About Torque Log cutting example

LOG CUTTING "Three friends go camping in the forest with their families. They start collecting wood to make a fire. They find a large, branchless log in the forest. One end of the log is very ...
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### Sign of distance/arm when finding moment/torque

I know that $M=Fd$, but when I have a negative moment, does the sign of the moment matter when I'm calculating for distance? If yes, then what would it mean when distance is negative?
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### What causes an arrow to rotate? [duplicate]

My intuition: In a system without air resistance, I would expect an arrow shot at an angle with its head pointing upwards to follow a ballistic trajectory without rotating around the horizon - because ...
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### Calculate weight distribution on 2D plane

I am trying to figure out how I can have a formula for the weight distribution on a square. But let me just describe what I am doing, We have the classical horizontal beam support problem And I we can ...
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### What exerts torque on a pulsar? [duplicate]

I'm modeling a pulsar as a rotating compact body with frequency $\omega(t)$, and magnetic dipole moment misaligned from the axis of rotation by angle $\chi$. It's straightforward to calculate the ...
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### Is Torque always defined about the axis of rotation?

My professor told me torque can be calculated about any point in space, but would such a torque ever make sense even if the particle is rotating about some other axis, on which the point does not lie?
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### Choice of axis in analysis of gyroscopic precession

In many demonstrations of analysis of gyroscopic precession, the analysis goes on by choosing two axes, one about which angular momentum is calculated, another about which torque of gravity is ...
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Consider a free body, not hinged about any point. If a force is applied to one end of the body, the body has a net nonzero torque about many points in space. About which will it rotate? Am I wrong in ...
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### What does the geometric product between displacement (or maybe position) and force vectors mean?

So work is measured in joules, which is newton * meter, and it is calculated by taking a scalar product between displacement and force vectors. And torque is very similar, it is newton * meter too, ...
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### How to calculate total moment around $z$-axis when the armlengths are not the same for all motors on a hexacopter?

I wonder how I can calculate the total moment around $z$-axis at a given rotational velocity for the motors on a hexacopter. My intuition tells me that motors that are more distant to center of mass ...
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1 vote
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### Axis of rotation of a spool unwinding and falling under gravity

There is a problem that asks for forces that apply torque around the axis of rotation on a spool of string that falls and unwinds under gravity. The spool falls straight down with a vertical string. ...
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### Interpret momentum applied on a rod when holding it from one end

Yesterday I started wondering exactly how much more effort it takes holding a rod from one of it's edged instead of from it's centre. Picture a rod, held by your hand from under it's centre. The force ...
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### Why does force decrease with increase in velocity in case power was constant?

Suppose an internal combustion engine burns the same amount of fuel every cycle (regardless of engine or car speed ) that means it creates the same pressure every cycle and the force on the piston due ...
Mathematically, torque induced gyroscopic precession may be modelled with the following equation:  {\displaystyle T_{\mathrm {p} }={\frac {4\pi ^{2}I_{\mathrm {s} }}{\ mgrT_{\mathrm {s} }}}={\frac {...