What is significance of torque

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SUMMARY

Torque is defined as the product of force (F) and the distance (r) from the pivot point, represented mathematically as τ = F * r. This definition is crucial for understanding rotational motion, as it parallels linear motion equations such as F = ma. The significance of torque lies in its ability to predict the behavior of mechanical systems, where twice the torque results in twice the angular acceleration, similar to how linear force affects linear acceleration. The discussion emphasizes the importance of torque in practical applications, such as using tools like wrenches and screwdrivers to apply rotational force effectively.

PREREQUISITES
  • Understanding of basic physics concepts, including force and acceleration
  • Familiarity with rotational dynamics, specifically moment of inertia
  • Knowledge of angular motion equations, such as τ = Iα
  • Basic mathematical skills to manipulate equations
NEXT STEPS
  • Study the relationship between torque and angular momentum in rotational dynamics
  • Explore the concept of moment of inertia and its impact on rotational motion
  • Learn about practical applications of torque in engineering, such as in machinery and vehicles
  • Investigate the differences between linear and angular motion equations
USEFUL FOR

Students of physics, mechanical engineers, and anyone interested in understanding the principles of rotational motion and its applications in real-world scenarios.

Arslan
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or you can say what is the physical interpertation of torque. i know the mathemetics of it but what's its significance in practical terms.
 
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What? You mean you want to know how it applies to the real world?

Like how you use a wrench to tighten a nut on a bolt? Or rev an engine to accelerate your car?
 
Using a screwdriver is a rather good way to feel what torque is.
 
let me put my question this way
why torque is defined as F*r why not F*r^2
 
Hi Arslan! :smile:

Torque is turny-force, and moment of inertia is turny-mass.

Mass is the ratio of linear force to linear acceleration …

twice the force gives twice the acceleration.​

Moment of inertia is the ratio of torque (angular force) to angular acceleration …

twice the torque gives twice the angular acceleration. :wink:
 
Arslan said:
let me put my question this way
why torque is defined as F*r why not F*r^2

Reasonable question.
The pragmatic answer is that your suggested alternative won't give you the right answer when you try to calculate what will balance what. Torque is a quantity, like Force that can be used to model and understand mechanical situations AND to predict what will happen. The proof of the pudding is in the eating.

The more rigorous answer is that angular momentum is a very basic quantity in the Universe - just as linear momentum is. The formulae for linear motion, such as
Force = mass times acceleration
momentum = mass times velocity
and others, are well known. (?)

There are equivalents in the 'rotational world' and Torque turns up in those formulae, along with Moment of Inertia and Angular Momentum etc.
You would need to read further if you want more details and some of those formulae.
 
Arslan said:
or you can say what is the physical interpertation of torque. i know the mathemetics of it but what's its significance in practical terms.

I think of torque as a force that causes rotational motion.

F = ma; here force F causes linear motion, with linear acceleration a.

Torque τ = Iα ; α is angular acceleration and moment of inertia I is related to mass.

Similarity between this 2 equations seem to be what is linear (motion in straight line) and angular (motion in circle).
 
Arslan said:
let me put my question this way
why torque is defined as F*r why not F*r^2
What would be the advantage of defining torque as F*r^2?
 

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