Calculating Angular Velocity & Revolutions for a Merry-Go-Round

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Homework Help Overview

The discussion revolves around calculating angular velocity and the number of revolutions for a merry-go-round that is being accelerated from rest. The subject area includes concepts of rotational motion and angular kinematics.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to determine the time required to reach a specific angular velocity using the formula for angular acceleration. They express uncertainty regarding the calculation of revolutions and seek clarification on relevant equations.
  • Some participants confirm the first part of the calculation and suggest using angular displacement to find the number of revolutions, while others propose alternative equations for angular motion.
  • There is a question about the appropriateness of using average angular frequency to find angular displacement, with a participant noting that acceleration complicates this approach.

Discussion Status

The discussion is active, with participants providing guidance on the equations needed for the second part of the problem. Multiple interpretations of the approach to calculating revolutions are being explored, but there is no explicit consensus on the best method yet.

Contextual Notes

Participants are navigating the constraints of the problem, including the need to account for angular acceleration and the implications of using average values in their calculations. There is an emphasis on ensuring the correct application of formulas in the context of rotational motion.

sauri
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A merry-go-round is accelerated from rest by a child at a steady acceleration of 0.2 rad.s-2.

1)How long does it take for the merry go round to reach an angular velocity of 1.4 rad.s-1?
2)How many revolutions does the merry go round (and the child) make in this time?

I believe I worked out the first one, where a=w/t. so t=w/a (t=1.4/0.2). Am I correct?.

However I can't understand the second part..is there an equation to find the number of revs?
 
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The first question, I think you're right.
For the second one, find the angle [itex]\theta=\frac{1}{2}at^2[/itex]
The revolutions are [itex]N=\frac{\theta}{2\pi}[/itex][/color]
 
is it ok to use w=[itex]\theta/t to find the angle?[/itex]
 
sauri said:
is it ok to use w=[itex]\theta/t to find the angle?[/itex]
[itex] <br /> No because this will only give you an average angular frequencey. As there is acceleration you need to use the equations phuncv87 posted.[/itex]
 

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