In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment, moment of force, rotational force or turning effect, depending on the field of study. The concept originated with the studies by Archimedes of the usage of levers. Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object around a specific axis. Another definition of torque is the product of the magnitude of the force and the perpendicular distance of the line of action of a force from the axis of rotation. The symbol for torque is typically
τ
{\displaystyle {\boldsymbol {\tau }}}
or τ, the lowercase Greek letter tau. When being referred to as moment of force, it is commonly denoted by M.
In three dimensions, the torque is a pseudovector; for point particles, it is given by the cross product of the position vector (distance vector) and the force vector. The magnitude of torque of a rigid body depends on three quantities: the force applied, the lever arm vector connecting the point about which the torque is being measured to the point of force application, and the angle between the force and lever arm vectors. In symbols:
{\displaystyle \tau =\|\mathbf {r} \|\,\|\mathbf {F} \|\sin \theta \,\!}
where
τ
{\displaystyle {\boldsymbol {\tau }}}
is the torque vector and
τ
{\displaystyle \tau }
is the magnitude of the torque,
r
{\displaystyle \mathbf {r} }
is the position vector (a vector from the point about which the torque is being measured to the point where the force is applied),
F
{\displaystyle \mathbf {F} }
is the force vector,
×
{\displaystyle \times }
denotes the cross product, which produces a vector that is perpendicular to both r and F following the right-hand rule,
θ
{\displaystyle \theta }
is the angle between the force vector and the lever arm vector.The SI unit for torque is the newton-metre (N⋅m). For more on the units of torque, see § Units.
Homework Statement
A body of water of depth D sits behind a vertical dam. The water and dam are in static equilibrium. Calculate the torque on the dam due to the water about an axis at ground level (that is, a depth D below the surface of the water).
Homework Equations
N (torque) = r x F
The...
Hi Guys and Girls, I new to here. I am Designer and recently I am studying the torque of a motor needed to turn a set of 20 agitators by using a belt. Let say each of the agitator have needed 2Nm to operate, so if I use a motor to operate 20 agitators how many of torque is needed. I have no idea...
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I am working on selection of motor for intermittent wrapping steel strip on a reel, intermittent because system is equipped with a sensor which triggers motor after the strip reaches a certain level in the buffer box and then motor stops when the level of strip falls below another fixed...
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I've recently came across this video (), where the authors use a motor to compress springs and therefore achieve locomotion. I've been thinking why is there a resulting downward net force. But i can't really figure it out.
Thank you for time :)
See the video from 1.16 minutes and...
My textbook says any torques associated with the internal forces acting in a system of particles are zero and therefore net external torque = total angular momentum/ time
First of all, what is net external torque? Is it just net torque? Is there a thing called internal torque?
Second, why is...
Homework Statement
A war-wolf or trebuchet is a device used during the Middle
Ages to throw rocks at castles and now sometimes
used to fling large vegetables and pianos as a sport. Model it
as a stiff rod of negligible mass, 3.00 m long, joining
particles of mass m1 = 0.120 kg and m2= 60.0 kg...
Homework Statement
A potter’s wheel—a thick stone disk of radius 0.500 m
and mass 100 kg—is freely rotating at 50.0 rev/min.
The potter can stop the wheel in 6.00 s by pressing a
wet rag against the rim and exerting a radially inward
force of 70.0 N. Find the effective coefficient of kinetic...
A rod is radially mounted on a motor shaft and provided with a flat end plate. By turning movement, the end plate will touch a pointed object, and the angle turned is measured.By the torque of the motor during acceleration and deceleration, a vibration and deflection happens on the rod. The...
The Classroom door is of width 50 cm. If the Handle of the door is 20 cm from the edge and Force of 5N is applied on the handle. Calculate the torque?
I have attached what I think is the answer. But the answer on the site from where I took this question is 0.8 Nm. Here is the answer the site...
Question 1:
What exactly is torque? I know this seems like a very vague question the answer of which can be found easily online, but I don't think any website online defines torque properly. The definition of force is a proper definition because it allows us to make predictions, if we know F...
I know that decoupling the 3 phase currents we get the id and iq (in rotor frame) currents which control the flux and torque respectively. But where does the relation come from?
i want to ask that in same gear which is true?
a)car accelerates best at the max torque rpm
or
b)car accelerates best at the max horse power rpm
which is true and why
we talk these conditions at same gear
thanks
I wanted to know how the ,mathematical concept of Torque comes(Like force comes from Newton's law). So i went and read university physics and feynman's lecture. and here is a problem I had. I am uploading a picture of Feynman's lecture, and stating my problem below about that part.
But since in...
< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >
Hey,
So I am not sure if this is in the right section but feel free to move it.
We are conducting an experiment at school at the moment and are having difficulty understanding all the theory...
Hi,
I saw a video online of a self balancing 2 wheeled car. Basically a motorcycle with a body though has a steering wheel rather than handle bars. It uses two gyroscopes spinning in opposite directions to keep it's balance and was wondering if a similar thing could be adapted for regular...
Hi All,
I'm confused with a particular question and I'm not entirely sure how the answer was derived.
A one-meter board with uniform density hangs in static equilibrium from a rope with tension T--The rope is connected .2m from the left end. A weight of 3kg hangs from the left end of the...
I've heard the analogy that a high torque car is like a bodybuilder, it is powerful but slow.
And a high horsepower car is like a sprint runner, it runs fast, but not as powerful.
Considering other factors constant.
if each tries to ride a bicycle to a certain speed,
and the runner is given a...
Hi, I'm having conceptual problems for solving this one.
1. Homework Statement
I drew a picture of this problem, which should show up below. Lengths x,a and b were given in the original picture.
A rotating closed cylinder is braked with a bar. Its brake shoe is pressed in respect of point B...
Hi, sorry for the title. I struggled to accurately describe my question in a short sentence.
I'm trying to understand if there would be a holding torque or not in the following scenario.
I'm referring to a motor which has a central stator and two permanent magnet rotor plates on either side...
Hi,
Sorry if this is in the wrong thread I'm new to the forums. I was recently talking my mate about how engines produce power and torque and how there's so many factors in it. I mentioned the length of conrod would be a factor but my mate disagreed that it has no effect on torque. To my...
I am facing problem in calculating the shaft torque for my system.
Motor is driving pulley and that pulley is coupled with belt with another big pulley (please refer attached file image).
Motor power 19.4 kw, Torque- 71.8 Nm, Motor Rated speed- 2580 rpm, motor shaft dia=42mm
Pulley dia (refer...
Homework Statement
Hello, I attempted solving a problem from my practice sheet, but got stuck on part B. If my part A is incorrect, please let me know!
Homework Equations
Not sure which equations to use!
The Attempt at a Solution
I don't think the solution is too difficult for part B...
Hello. Suppose I have a coordinate system with the origin at the center of mass at rest of some rigid object and I wish to calculate the total change in angular momentum of the object with respect to it's center of mass.
If I apply a torque to the object, that also happens to be an unbalanced...
Ive been struggling with this for days trying to make sense of a rpm vs torque chart I've seen recently.
The chart states the engine load was measured 100% 70% 40% 0% and at 1000 2000 3000 4000 rpm. How is this done if using a chasis dyno?
I attached the chart for reference.
That's my...
hi,
i have 8000 lb machine it has 4 wheels (just like car), i want it to move on 2 ft/sec speed on cast iron wheels with steel track at flat surface. radius of every wheel in 5 inch. what will be the torque required to move this machine?? and what will be the torque on each wheel?? i want to...
Hi all,
I was trying to simulate a direct torque and flux controlled induction motor in simulink.
Even though I've managed to control torque within the band, i can't seem to be able to control the flux.
It stays for a while within its hysteresis band and escapes after about 0.1 sec and keeps on...
Hello everyone. The physics forum is a great online community, and I used to spend a lot of time browsing the philosophy pages. But now I've had to register and post, because I've got a very specific problem with regards mechanical engineering.
My problem is relating to torque transmission...
Suppose that there's a wheel. A constant torque is applied to the wheel from the central axis.
What is the relationship between the amount of force received by each particle on the wheel in relation to the distance each particle is away from the axis?
Given :
A (hypothetical) wheel with a m.o.i. of 1 lb*ft^2
Radius of wheel = 1.9099 inches, therefore circumference of wheel = 1 foot
The wheel is at rest, i.e. zero rotation speed.
A torque of 1 ft/lb is applied for 1 second
Is the result a rotation of 1 r.p.s. (60 r.p.m.) ?
thx
Mike
Capacitor-start induction motors use a capacitor in series with the start winding to create torque to start the motor. After the motor gets nearly up to full speed, a switch takes the capacitor out of the circuit. I understand the torque is caused by the phase shift created by having the...
I'd like to calculate how much torque a hollow cylinder along its axis can take before it will start to buckle. The cylinder is held at one end, and the torque is applied equally in discrete intervals along the length of the cylinder.
In the example image above, the hollow cylinder is mounted...
Hello guys,
I have been trying to calculate the maximum torque that can be applied to my driveline through regenerative braking, using the equations from this paper: https://smartech.gatech.edu/bitstream/handle/1853/47660/sambamurthy_aravind_201305_mast.pdf?sequence=1
I have been using the...
Homework Statement
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Homework Equations
theta = TL/GJ
t(max)= Tc/J
The Attempt at a Solution
The two questions i have are rather similar so i put them up at the same time, i hope that's okay.
For the first one ( the first link) i started by...
Hi,
I'm currently doing a small racing game where I allow players to tweak their car's engine (control number of cylinders, cylinder bore/stroke, turbo chargers, etc).
I've understood the very basics of how combustion engines work but I'm still struggling on how to calculate engine torque...
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I'm looking to find out how torque is used to prevent cranes from falling over.
I have to write a report about mechanics in the real world and am trying to decide if this would be a good topic.
Is anyone able to explain it to me?
I understand the right hand rule and the equition, but why is the direction of the torque perpendicular to the force on the counter clockwise side of the force and crossing the rotational point?
Hello,
I have a three phase brushless motor and was trying to measure its torque and speed using a torque sensor. The motor will first go to its maximum speed which is about 6000RPM, then I applied a brake to decrease its velocity. Here is what I get as a result of data acquisition :
The...
Good morning,
I have little problem here and I've come here with hopes of a solution!
I'm currently messing with a rotary to linear pressure cycling system. The size of the air cylinder has already been decided and I'm simply trying to design around it.
Here are the specifics! I've added a...
Hi i want to choose a motor for a project i am working on and i have a structure weighing approx 2kg which is to be run at 1000 RPM. So my question is what should be specifications of the motor i am to buy ,more specificly the torque required to run the structure and the power rating?
i was...
I have an engine with the following specifications:
305 cc, 4-stroke single-cylinder.
Torque : 18.53 N m @ 2800 rpm.
Weight of the car 275kg
Coefficient of drag:1.15
Frontal area: 0.9177m^2
Rolling resistance:0.04482
Engine wheel efficiency: 78%
How can i calculate the Max. acceleration and...
Homework Statement
A cylindrical rod of length w carries a current I as shown(perpendicular to B) and is bathed in a field B perpendicular to the plane in which is a " shaped rail. The rod rolls without slipping on the rails, its length perpendicular to the two parallel rails and equal to the...
Hi,
I have a question regarding the forces applied on an object that create the torque. I understand that the resulting torque is pos if the object turns counter clock wise and is neg if it turns clock wise and that you can also use the right hand rule to find the direction of the net torque...
Hello,
1. Homework Statement
A spherical continuous ball is sliding with a constant velocity v along a frictionless lane. Thereafter it enters an inclined surface (the angle between the surface and the horizontal plane is α) with the coefficient of friction µ between the ball and the surface...
Hi
I've been learning about angular momentum and torque, and today I learned that torque actually has a direction that is not simply the direction of rotation.
I saw about the right-hand rule to establish which direction the torque is going in.
My question is - if an object is rotating, will...
Hi everyone,
I am making a hexapod ( six legged walking mechanism ) which walking by keeping 3 alternate legs in air and other 3 on ground, pushing the body ahead, also known as tripod gait. The basic structure of model and one leg are shown in the pictures. I want to calculate the torque...
Hello
I'm new here. I have an interest in physics and have spent the day educating myself on a few concepts. I've stumbled across the concept of angular momentum and I am struggling to understand a particular aspect...
I understand in principle the idea that angular momentum is conserved...
Homework Statement
A tradesman sharpens a knife by pushing it against a grindstone with a given applied force. The grindstone is 28kg, 15 cm in radius, is originally going at 200 rpm but is slowed down to 180 rpm over 10 s by applying the knife. The coefficient of kinetic friction is 0.20...
Homework Statement
The problem
Direct imgur link to problem: http://i.imgur.com/QCc0zj6.jpg
Homework Equations
\alpha = \frac{\tau_{net}}{I}
I = \frac{1}{2}MR^2
\tau = rF = rmg
The Attempt at a Solution
I have figured that the moment of inertia of the entire system must be used for...
If there is a uniform ball rolling without slipping on an inclined plane, does gravity provide a torque, translational force, or both? I'm just really confused about forces vs. torques i guess?