Questions tagged [torque]

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

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Torque and angular acceleration in elliptical orbit

I am stuck in a supposedly simple aspect. Consider the Sun-Earth system. The torque is zero and angular momentum is conserved. $L = I\omega$ is constant, but since $I$ changes, $\omega$ should change ...
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Traslation of a bar on a plane - Contrasting results

I have a bar which can translate on a plane (gravity along y), at estremity A there are two forces and a moment, G is the center of mass, here I applied the gravity force: The dynamic equations are: ...
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How to calculate torque required move this cart? (Description) [closed]

Weight of cart is 2kg It has two wheels on back, each if 6cm It's front half is in contact with surface and has kinetic friction coefficient = 0.75 The cart has to move at constant velocity 1m/s ...
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Why do the inner tyres of a vehicle rise when taking a turn at high speeds?

When a person cycles at high speed on a turn, his body bends inwards, to raise the horizontal component of the normal reaction to provide the centripetal force for the turn. The more the speed is, ...
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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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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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Conceptual question about wheels

I am trying to understand quite naively wheels in a specific framework. Intro We normally think of squares and circles as different concepts of shapes, but I am reframing it that both are polygons ...
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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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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 ...
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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 ...
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Why cars have transmission gears? [closed]

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 ...
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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 ...
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45 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 ...
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Isn't inertia experience by person in moving bus same as torque

When a bus moves suddenly, the person standing in it tilts backwards. This concept is explained using inertia(tendency of body to resist change in its state of motion) but when the bus moves suddenly, ...
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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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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. ...
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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 ...
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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 $I= \gamma mR^2$ ...
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2answers
62 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 ...
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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 ...
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Torque Equation [closed]

There are two torque equations. and I'm confused about when to use which one given a certain scenario.
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22 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 ...
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95 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 ...
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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 ...
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3answers
85 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-...
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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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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;...
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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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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 ...
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36 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 ...
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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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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 ...
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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 ...
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143 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 ...
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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 ...
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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 ...
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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 ...
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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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47 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,...
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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 $$ \vec\tau={\frac{{\mu}_0 m^2}{2\pi z^3} }\hat{z} $$ ...
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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.
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86 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 ...
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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!
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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 ...
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3answers
66 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 ...
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65 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 ...
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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 ...
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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 ...