Calculating Torque for 10 cm Axle & 100 cm Wheel

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    Axle Torque
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Discussion Overview

The discussion revolves around calculating the torque required to rotate an axle and wheel system, specifically with a 10 cm diameter axle and a 100 cm diameter wheel, while considering the effects of a hanging weight of 10 kg and later 11 kg. Participants explore the implications of these calculations in the context of mechanical design and energy considerations.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant asks how much torque is required to rotate the axle with a diameter of 10 cm when a 10 kg weight is hanging from the wheel.
  • Another participant suggests using the formula T = Fr, where the force is derived from the weight of the hanging mass.
  • There is a discussion about the need for additional torque to account for the moment of inertia of the axle and wheel system, as well as the acceleration of the hanging mass.
  • One participant calculates that the torque required to prevent the weight from falling is 981 Nm, based on the force exerted by the weight and the radius of the wheel.
  • Another participant raises a question about the impact force if the 10 kg mass falls freely from a height of 20 cm, discussing variables that affect the impact force.
  • There is a follow-up question regarding the torque required to lift an 11 kg weight, with calculations suggesting it would be 1079 Nm.
  • Some participants express confusion regarding the clarity of the original question and the calculations presented.

Areas of Agreement / Disagreement

Participants generally agree on the need to calculate torque based on the weight and dimensions provided, but there are multiple competing views on the specifics of the calculations and the implications of energy use in the system. The discussion remains unresolved regarding the clarity of the original question and the exact calculations needed.

Contextual Notes

Participants mention the dependence of torque calculations on factors such as angular acceleration, moment of inertia, and the material properties of the axle and wheel. There are also unresolved questions about the assumptions made in the calculations and the specific conditions under which they apply.

siva surya
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when 10 cm rope pull axle and wheel and in which axle is 10 cm in diameter and wheel is 100 cm in diameter in which wheel hangs a weight 10 kg of metal ..in this how to much torque is required to rotate axle?
 
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Could you draw a diagram? Or rephrase your question? I can't understand the question.

It may be that:
T = Fr where the force is due to the 10kg mass and r is the radius of the axle?
 
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in this
1.how much torque is reuired to rotate axle of diameter 10 cm
2.and on the other end wheel is attached of diameter 100 cm and hang with 10 kg of weight
3.then in how many kg should be axle and wheel metal ?
 

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siva surya said:
in this
1.how much torque is reuired to rotate axle of diameter 10 cm
2.and on the other end wheel is attached of diameter 100 cm and hang with 10 kg of weight
3.then in how many kg should be axle and wheel metal ?

1. It depends on how fast you want the system to accelerate.
T = Iα
Where T is torque, I is moment of inertia and α is angular acceleration.

The moment of inertia depends on geometry and mass:
https://en.wikipedia.org/wiki/Moment_of_inertia

The above only considers the torque required to accelerate the axle & pulley, additional torque will be required to accelerate the hanging mass upwards.

3. The mass of the axle & wheel will be the volume multiplied by density. The required geometry will depend on the forces applied, in other words it needs to be of a certain size (and mass) so it doesn't break.

Is this homework? Or a real project? Maybe you are trying to design a hand winch?

https://www.google.co.nz/search?q=h...Cc#q=hand+winch&tbm=isch&tbs=isz:lt,islt:svga
 
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i like to design no energy machine
 
ya like to use gravity as energy
 
Gravity is not considered a source of energy (but you can use gravity to store energy from another source).

siva surya said:
1.how much torque is reuired to rotate axle of diameter 10 cm
2.and on the other end wheel is attached of diameter 100 cm and hang with 10 kg of weight

The torque must be at least..

= (10Kg * 9.81) * 100/10
= 981 Nm

That torque will stop the weight falling. If you want to raise the weight then (as billy said) you need to tell us how fast you want it to accelerate and the moment of inertia of the pulleys etc. Friction?
 
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if the 10 kg mass falls as free fall and create impact force means what's the impact force on there
in which mass 10 kg
height 20 cm
whats Newton there
 
Last edited by a moderator:
  • #10
The impact force depends on what the 10kg mass is made of and what it hits. One way to visualise this is that it will be higher for concrete than carpet because the "stopping distance" is shorter.

If you assume it hits something like modelling clay and has constant deceleration you can estimate using..

V2 = U2 +2as

where
U2 = velocity at impact
V2 = velocity after impact, probably zero
a = acceleration
s = distance (eg depth of impact crater)

So you could measure the depth of the impact crater and plug in the numbers to estimate the deceleration "a".

Then use F = ma to estimate the implied impact force.

The results will be very approximate. In the real world it's better to attach an accelerometer to the mass and measure "a".
 
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  • #11
how much torque is required to pull up to weight 11 kg from 100 cm through wheel and axle?
 
  • #12
CWatters said:
The impact force depends on what the 10kg mass is made of and what it hits. One way to visualise this is that it will be higher for concrete than carpet because the "stopping distance" is shorter.

If you assume it hits something like modelling clay and has constant deceleration you can estimate using..

V2 = U2 +2as

where
U2 = velocity at impact
V2 = velocity after impact, probably zero
a = acceleration
s = distance (eg depth of impact crater)

So you could measure the depth of the impact crater and plug in the numbers to estimate the deceleration "a".

Then use F = ma to estimate the implied impact force.

The results will be very approximate. In the real world it's better to attach an accelerometer to the mass and measure "a".
how much torque is required to pull up to weight 11 kg from 100 cm through wheel and axle?
 
  • #13
110 Nm
 
  • #14
siva surya said:
how much torque is required to pull up to weight 11 kg from 100 cm through wheel and axle?

In post #8 I showed you how to calculate the torque for 10kg...

CWatters said:
The torque must be at least..
= (10Kg * 9.81) * 100/10
= 981 Nm

For 11kg the sum becomes..
= (11Kg * 9.81) * 100/10
= 1079 Nm

or has your system changed?
 
  • #15
PS: It's hard to understand your English.
 

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