Torque Help -- Tension in a Hoist Cable

Click For Summary

Discussion Overview

The discussion revolves around calculating torque and power in the context of a hoist system, specifically focusing on the relationship between torque, angular acceleration, and power output. Participants are addressing specific parts of a problem related to these concepts.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant mentions a frictional torque of 1500Nm and calculates a force of 7582.5N based on a drum shaft radius of 1.5M, questioning whether they need to calculate angular acceleration to find torque.
  • Another participant states that power can be calculated as Torque multiplied by angular velocity, implying that torque is not simply doubled.
  • A later reply confirms that the torque value will differ when considering constant speed, suggesting that the earlier calculations may not apply in that context.

Areas of Agreement / Disagreement

Participants express differing views on the calculation of power and the relationship between torque and angular velocity, indicating that multiple competing interpretations exist regarding the problem's requirements.

Contextual Notes

There are unresolved assumptions regarding the definitions of torque and power in the context of the problem, as well as the implications of constant speed on torque calculations.

smr101
Messages
72
Reaction score
0
Hi, I'm having a problem with 3. (b) (ii) here.

I know that the frictional torque is 1500Nm and that from (b)(i) being 5055N I assume this is multiplied by 1.5M (drum shaft radius) which gives me 7582.5N. Do I have to calculate the angular acceleration of the drum from here, which could then give me the torque? And if so, how?

Help much appreciated. Answer and solution below.

9fVTB.jpg

1dUdy.jpg
 
Physics news on Phys.org
In addition to this how is the power calculated for (b)(iii)? I understand it is two times the torque but why?

Thanks.
 
Two times the torque?

Power = Torque * angular velocity
 
Hi, I'm having a problem with 3. (b) (ii) here.
I know that the frictional torque is 1500Nm and that from (b)(i) being 5055N I assume this is multiplied by 1.5M (drum shaft radius) which gives me 7582.5N. Do I have to calculate the angular acceleration of the drum from here, which could then give me the torque? And if so, how?

Yes.

First calculate the angular acceleration from the velocity of the rope and the dimensions of the drum.

Then what equation relates torque and angular velocity?
 
Last edited:
PS: The Torque will not be the value calculated earlier because part iii) says "at a constant speed".
 

Similar threads

HNC Dynamics help please -- Hoist cable looped over a winding drum
  • · Replies 1 ·
Replies
1
Views
3K
Finding the torque required for telescopic cable mechanism
  • · Replies 15 ·
Replies
15
Views
5K
Engineering Loads on a shaft with V-Belts
  • · Replies 2 ·
Replies
2
Views
3K
As Simple Hoist System Problem - Given Answer Wrong?
  • · Replies 2 ·
Replies
2
Views
3K
Rotation of a drum attached to a spring
  • · Replies 9 ·
Replies
9
Views
2K
Mechanical Principals - Drive belt tension and load torque
  • · Replies 3 ·
Replies
3
Views
4K
Electric chain hoist: need help with control circuitry
  • · Replies 25 ·
Replies
25
Views
5K
Tension Question for Ship Container and Wind Gust
  • · Replies 12 ·
Replies
12
Views
1K
Torque to lift object by cable on a drum accelerating
  • · Replies 8 ·
Replies
8
Views
4K
Designing a Patient Hoist Winch: Factors of Safety and Power Calculations
  • · Replies 5 ·
Replies
5
Views
3K