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

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4answers
188 views

Why does Torque exist?

Specifically, why does force increase with the moment arm? What about making a perpendicular force farther away from the axis of rotation increases it? How does the moment arm cause that?
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0answers
15 views

DC Generator Torque control

Consider a DC generator connected to a hydraulic turbine. By modifying the excitation current provided to the stator you can create a torque variation, maintaining a constant power of the ...
0
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1answer
47 views

Torque at a bar [closed]

Take a look at the image below. At the point B a motor is spinning really fast in anticlockwise direction. The motor should be connected to a propeller (I didnt draw it) that will pull the bar upwards ...
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0answers
36 views

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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0answers
23 views

Centre of gravity: Adjusting position

If an object is freely suspended from a pivot, why does the centre of gravity fall directly below that pivot? Would this be the same in non-uniform gravitational fields?
1
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1answer
61 views

Homework Question: Moments [closed]

Can someone please explain this question? My work: If we take B to be the pivot then as B gets closer to mg the torque due to mg gets smaller, but I don't really see how this affects the force F (I ...
2
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1answer
56 views

Torque on a right angle triangle [closed]

I am attempting a question regarding the torque on a right angle triangle. The triangle is pivoted along the adjacent axis, there is no force acting on the opposite side, however there is a 12N force ...
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0answers
15 views

How to determine the right motor to rotate things? [closed]

Me and my teammates are trying to produce a motorized rotating bench. we want to rotate the bench to the other side if one of them get wet by the rain. we are currently doing the proposal for our ...
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0answers
43 views

Converting torque to angular velocity

Given the torque of a system, is it possible to convert this torque to the angular velocity of the object? I calculated the torque exerted by wind on a blade, however, now I need the RPM. To get the ...
1
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1answer
172 views

Calculating the tipping point of a lamp post

So I'm designing an outdoor lamp post and trying to calculate whether it will withstand the heavy winds at the worst case scenario. Here are the parameters and what I've done so far: The lamp post is ...
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0answers
37 views

Loop on flat table, magnetic vs gravitational torque

My question is on the second problem from here, number 26.57, about the torque on a loop with current through it lying on a table. ...
0
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1answer
44 views

Angular acceleration from torque and radius

The story is about wheel. I have a wheel and I need to know it's actual angular velocity(which doesn't mach Vcar_longitudal / r). What I have access to is torque ...
0
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1answer
41 views

How to apply torque impulse

In the below question, can we apply conservation of Angular Momentum? If not, why? Moreover how do we apply Torque impulse to the system ? The contact force between the cylinders will be normal to ...
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1answer
17 views

Why doesn't Torque of masses on a pulley depend on the friction between the rob and the pulley according to a question in the physics 1 book

What I don't understand about this question is: why is the torque of the masses on the pulley equals the weight of each mass times the radius. I thought that the torque on the pulley from the ...
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0answers
5 views

Measuring thrust with vertical torque

I would love to measure the thrust of a series of small rocket motors for a science project but having trouble figuring out the math.. A rocket motor with mass m1 is r1 meters from axis of rotation ...
0
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2answers
63 views

Damped Pendulum (generalised)

I know the differential equation for the swinging of a simple pendulum: $\displaystyle\frac{\partial^2\theta}{\partial t^2} + \left(\frac{g}{L}\right)\sin\theta = 0$ where: $L$ is the length of ...
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2answers
46 views

Torque: The T-shaped stick problem

This is a problem that I have been unable to solve for some time. Imaging a T-shaped stick, as shown in below image, which do not deform in any appreciable way and has pivot point at the tail of the ...
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1answer
22 views

Why, here, the torque with respect to bob is zero?

here, as you see, is a diagram of a pendulum with moving pivot along x-y surface. This picture was obtained from a journal in which this equation was written: $$F_x l \cos\theta = F_y l \sin\theta ...
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0answers
24 views

Conservation of angular momentum in a system under torque

Let's say we have a particle $A$ like this which is located in the disk $c$. Consider that the particle itself is not moving, but in general it is constrained to the semicircle $d$, in that if it ...
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2answers
30 views

What determines whether a mobile will hang in stable or unstable equilibrium?

Asking for a friend trying to make a Calder-style hanging mobile: https://www.google.com/search?q=mobile+calder&tbm=isch I understand torque just well enough to get it to balance (theoretically). ...
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2answers
45 views

Why can't a force between two particles exert a torque?

Let's say I have two particles which exert a mysterious force between them. Say they lie on the x-axis. Newton's 3rd law tells us that the force on the two particles due to the other must be opposite ...
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2answers
94 views

Why don't barbells tip over when a 45 is placed on one side?

A standard barbell is 45 pounds, as is the heaviest weight available in most gyms. When a weight is placed on the side of a barbell, some of the barbell is to the "outside" of the weight, like so, so ...
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2answers
72 views

Direction of torque due to magnetic moment

I have a problem with determining the direction of torque due to magnetic moment on a current loop. Since the torque is defined as $$ \tau = p_m \times B $$ so I guess the direction of the torque ...
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0answers
57 views

Parallel axis theorem non-uniform density [closed]

The parallel axis theorem says that if the moment of inertia of a body rotating about the body's centre of mass is $I_{cm}$, then the moment of inertia of the body rotating about an axis parallel to ...
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2answers
73 views

What exactly is a torque?

I know there are a number of questions concerning torque on this site but I still don't quite understand what it is. A video by veritasium on gyroscopic precession ...
3
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1answer
34 views

Mechanics principle

When two forces of equal magnitude, opposite in direction and parallel act on an object, the object will rotate without having translational speed. On the other hand, when three concurrent forces ...
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1answer
46 views

Four bar linkage moment transmission

The question is. I know the angular velocity of $d$ after applying dynamic mechanics and the constant angular velocity of $b$ of $2\pi\ \text{rad/s}$ and I know the input moment of the power source ...
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1answer
65 views

How do I handle elastic contacts in a simulation with friction [closed]

I'm trying to simulate a wheel as it hits the ground. Problem 1 Suppose a disc is dropped from a height. It has initial velocity of $-x,-y$ caused by throwing and gravity. It has no initial angular ...
0
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0answers
28 views

Weight placement of turning motorcycle and traction

In the motorcycle racing world it seems that there's advice that one should place their weight on the outer foot rest when turning at high speeds, from some forums I've been looking at it seems like ...
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0answers
30 views

Forces in material removal (cutting, grinding, sanding, etc.)

A. Suppose a circular saw is spinning at a certain angular speed. When it starts to cut into the material, removing chips of the material or abrading it, the speed drops. The drop in speed depends on ...
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0answers
46 views

What is the derivation of $r*F=Iα$? [duplicate]

Please give me the derivation of the formula r*F=Iα for extended body. where, F=applied force r=distance between point of rotation & point where force is applied I=moment of inertia of the body ...
0
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1answer
53 views

Is a rotor balanced at constant angular velocity?

I have an asymmetrical rotating part. It vibrates its housing and emits audible noise. I need to add weights to ensure smooth rotation. However, I am constrained in which regions I can add ...
1
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1answer
84 views

Force (torque) to break a bike handlebar? [closed]

Few weeks ago a neighbor manage to hit my bike with his car while the bike was parked next to a wall, check the picture. One side of the handlebar was at the wall and the door of his truck hit ...
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1answer
42 views

can a single force rotate an object. not a torque

Can a single force (not a torque) rotate an object? How can the bar below fall given the force $\mathbf F$?
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1answer
48 views

With radian as a unit, should action and angular momentum have the different units?

If one accepts radian as a fundamental unit, does it make sense that action and angular momentum have units differing in radian to the power of one? The same question applies for energy and torque. ...
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2answers
74 views

Angular momentum changes depending on orign

Consider the image below where we have two point masses $m_1$ and $m_2$ with different masses which are rotating around a fixed axis with angular velocity $\omega$. If the origin is placed on the axis ...
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0answers
11 views

Stick stands in the corner then starts to fall, when will it detach from the wall? [duplicate]

A thin homogeneous stick stands on the smooth(no friction) floor, leaning against a smooth wall,stands absolutely vertically. (Imagine a corner).Then it starts to fall(with zero initial velocity).What ...
1
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1answer
38 views

Torque as if magnetic force were concentred in mean point

From what I see in my textbook and several on line resources (such as this, p. 8-8), I am tempted to think that the magnetic force $I\boldsymbol{\ell}\times\mathbf{B}$ acting on a straight conducting ...
1
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1answer
61 views

Rotational equilibrium Paradox

A block of mass M and height h is moving on a rough surface of coifficent of friction 0.5 .The block is moving with a velocity v at some instant. if we balance the torque due to frictional force and ...
0
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1answer
23 views

Changing angular momentum with no forces to do torque

Suppose a particle of mass $m$ moves in a straight line at velocity $v$ some distance away from an axis, as shown here at times t1 and t2 (where the axis of rotation is located at the origin of the ...
0
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1answer
55 views

Torque and Angular Momentum

An ice skater is spinning in a circle with an angular velocity, $\omega$, and rotational inertia $I$. Let's say that the skater then pulls his arms directly inwards at a constant rate over a time of ...
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0answers
46 views

What kind of torques cause an object to precess?

In studying precession, my textbook (Taylor's Classical Mechanics) makes the assumption that a top spinning about its symmetric axis, but tipped at an angle $\theta$, will precess nicely so long as ...
0
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1answer
48 views

Angular acceleration of a car door [closed]

http://imgur.com/F3eAF9F Edit: i uploaded to the site but it came out really blurry so heres the imgur link I don't get the solution at all, where does the -ma r cos theta come from? (Sorry on my ...
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2answers
90 views

Couldn't high gear ratio replace need for high torque engines?

I've noticed that there is a correlation between displacement and torque, so trucks, SUVs etc. have large displacement engines to produce lots of torque to move heavy loads. Sports cars have lower ...
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0answers
53 views

How to calculate motor torque & rpm

I watched a DIY video recently about a brushless DC motor. How would one go about calculating the max torque & max rpm (under no-load & a given load conditions) of that motor based on the ...
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0answers
24 views

How can I calculate the torque of draw force which affect on spinning ball flying in the air?

I am studying the Magnus effect on a flying ball i have calculate the magnus force but i trying calculate the angular acceleration, because the angular velocity of the ball is not constant. I have ...
0
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0answers
25 views

What point is the torque on a loop in a magnetic field taken about?

I know that the torque on a loop kept in uniform magnetic field is given by $$\vec{\tau}=\vec{M}\times\vec{B}$$ where $\vec{M}$ is magnetic moment. Now, can I take this torque about any point in ...
-1
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1answer
68 views

What is a moment/torque?

What is a moment/torque? i know the formulas m = fxd (Nm), I know how it works, what is does etc. But think of it fundamentally, how is it possible, that a force becomes greater when the arm of an ...
0
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1answer
280 views

Angular momentum paradox with 2 identical gears

Consider two identical gears touching each other. The system is friction less. One has a handle that you use to apply a torque on the entire system. If you turn the handle, there will be a non-zero ...
0
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2answers
52 views

Torsion and twist in solid cylindrical beam

Well given a beam (as shown), a solid cylinder with radius R. A Torque $T$ applied to it, I need to solve the angle of twist ($\theta$) at the position where the torque is applied ($z$). The basic ...