What is the angular velocity of a cylinder in rev/hr

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Discussion Overview

The discussion centers around calculating the angular velocity of a cylinder, specifically an offset press cylinder, in revolutions per hour (rev/hr). It involves the relationship between linear speed and angular velocity, as well as the conversion between different units of measurement.

Discussion Character

  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant presents a calculation for angular velocity using the formula \( v = r\omega \) and provides a result of approximately \( 106821 \text{ rev/hr} \), expressing concern that this value seems too large.
  • Another participant confirms the calculation is correct, noting the high number of revolutions due to the conversion from seconds to hours.
  • A participant expresses confusion about how to incorporate the terms "rev" and "rad" in equations, indicating a lack of understanding of their relationship.
  • A later reply clarifies that one revolution corresponds to an angle of \( 2\pi \) radians, establishing a connection between revolutions and radians.

Areas of Agreement / Disagreement

Participants generally agree on the correctness of the angular velocity calculation, but there is uncertainty regarding the interpretation of revolutions and radians in equations.

Contextual Notes

There may be missing assumptions regarding the context of the cylinder's operation and the appropriateness of the linear speed value used in the calculation.

karush
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An offset press cylinder has a $13.37\text {in}$ diameter.

The linear speed is $\displaystyle\frac{16.53 \text{ ft}}{\text{sec}}$

What is the angular velocity $(\omega)$ in $\displaystyle\frac{\text{rev}}{\text {hr}}$

from $v=r\omega$ then

$\displaystyle\frac{16.53\text{ ft}}{\text{sec}}
\cdot\frac{3600\text {sec}}{\text {hr}}
\cdot\frac{1}{6.685\text{ in}}
\cdot\frac{12\text { in}}{\text {ft}}
\approx\frac{106821\text{ rev}}{\text{hr}}$

this ans looks to large?
 
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Re: what is the angular v of a cylinder in rev/hr

You answer is correct...it is spinning many times per second and there are many seconds per hour. :D
 
Re: what is the angular v of a cylinder in rev/hr

well that cool...

I still don't know how to really deal with the words "rev" and "rad" in an equation?
 
Re: what is the angular v of a cylinder in rev/hr

karush said:
well that cool...

I still don't know how to really deal with the words "rev" and "rad" in an equation?
A rev(olution) is once around the circle. This corresponds to an angle of 2pi radians. Thus 1 rev = 2pi rad.

-Dan
 

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