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The torque

Referring back to Figure 6 , we find that the torque produced by this force is equal to the product of the distance from the center to P and the tangential orperpendicular component of the force vector.

Therefore,

T = Ft*r, or

T = F*sin(A)*r

where

  • T represents torque
  • Ft represents the tangential component of the force vector
  • r represents the distance from the puck to the center of the circle
  • F represents the force vector
  • A represents the angle between the force vector and the line from the puck to the center of the circle

Example scenarios

This section contains several example scenarios involving torque.

Net torque on the Lazy Susan turntable

The turntable discussed earlier, which has a radius of 24 cm, is spinning clockwise. You press your fingers on the east and west sides of the turntable with equalforces of 6.67 N. The coefficient of friction between the turntable and your fingers is 0.75. What is the net torque on the wheel?

Solution:

The 13.3 N force on each side of the table creates a tangential kinetic friction force on each sideof the table equal to

Ft = 6.67 N * 0.75

Each force is in the opposite direction of the direction of rotation.

The net torque is equal to the sum of the torques.

Each torque is equal to the product of the force and the distance from the center of the turntable to the point at which the force is applied.

T = 2 * Ft * r, or

T = 2 * 6.67 newtons * 0.75 * 24 cm

Entering this expression into the Google calculator gives us

T = 2.4 joules

However, this is one case where the Google calculator gives us a misleading answer. We know that torque is not measured in joules. Instead, torque ismeasured in N*m. Therefore, the net torque on the turntable is

T = 2.4 N*m

A door-closing scenario

When viewed from above, the scenario is a door that is open. From above, the wall to which the door is attached can be represented by a horizontal line that runs from west to east. The door can be represented by a line segment at an angle of about 45 degreessouth of east. The line segment (door) is attached to the wall at the upper-left end of the line segment. That is the point where the door is hinged, and that point is the axis ofrotation for the door.

Assume that the axis of rotation extends out of the page towards you.

The door will need to rotate about 45 degrees counter clockwise to become flush with the wall and be closed.

A person is standing on the north side of the wall pulling on a rope that is attached to the door. The rope is attached 11.5 cm from the hinge and makes a 45degree angle with the surface of the door. That person pulls on the rope with a force of 51 N.

Using the door hinges as the axis of rotation, find the magnitude of the torque that is exerted on the door. What is the sign of the torque.

Solution:

This solution is based on the cross product from Figure 4 .

The magnitude of the torque is given by

T = r * F * sin(angle), or

T = 11.5 cm * 51 newtons * sin(45 degrees)

Entering this expression into the Google calculator gives us

T = 4.15 N*m

Questions & Answers

how can chip be made from sand
Eke Reply
is this allso about nanoscale material
Almas
are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
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William
currently
William
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
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Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
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Source:  OpenStax, Accessible physics concepts for blind students. OpenStax CNX. Oct 02, 2015 Download for free at https://legacy.cnx.org/content/col11294/1.36
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