Calculate Maximum Velocity of Girl on Swing

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    Maximum Velocity
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Homework Help Overview

The discussion revolves around calculating the maximum velocity of a girl swinging on a swing, with specific details about the swing's height and length. The problem involves concepts from mechanics, particularly potential and kinetic energy, as well as the motion of pendulums.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore whether the maximum velocity occurs at the lowest point of the swing and discuss the relationship between potential and kinetic energy. Some express confusion about the role of mass in energy calculations and the implications of gravitational acceleration. Others question the relevance of certain equations and concepts, such as the period of a pendulum and the nature of the swing's motion.

Discussion Status

The discussion is active, with participants sharing various thoughts and equations related to energy conservation and motion. Some guidance has been offered regarding the use of energy principles, but there is still a lack of consensus on the best approach to take, and several interpretations are being explored.

Contextual Notes

Participants note constraints such as the absence of mass in calculations and the need for clarity on height references in energy equations. There is also mention of specific angles and trigonometric considerations that may not be necessary for solving the problem.

  • #31
this book I have says stuff like potential energy goesinto kinetic energy if you refer to the conservation of mechanical energy.
 
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  • #32
Yes but it says what is her maximum velocity:

So v=sqrt 2gh @ 1m = 4.43 m/s but v=sqrt 2gh @ 2m = 6.26 m/s ... (so this does not make sense to me...)
 
  • #33
the height is the y direction between the heighest point and the lowest point. does that make sense?
 
  • #34
yes... get it now... fwwwww lol... thanks for all you help!
 
  • #35
oh! well then you'd think that technically there still is a potential energy at the lowest point, since it's 1 meter above ground, which means v=sqrt2ghfinal - sqrt2ghinitial, but that's incorrect, because it violates the law of conservation of energy. but hm...maybe h=2meters, because it's 2 meters from the ground. I'm really sorry if you are confused. I am too!
 
  • #36
Rayquesto said:
oh! well then you'd think that technically there still is a potential energy at the lowest point, since it's 1 meter above ground, which means v=sqrt2ghfinal - sqrt2ghinitial, but that's incorrect, because it violates the law of conservation of energy. but hm...maybe h=2meters, because it's 2 meters from the ground. I'm really sorry if you are confused. I am too!

This problem has little to do with the actual Potential energy, and everything to do with the CHANGE in Potential energy.
In all problems, we get to set where zero height is, and invariably we choose either the lowest point, the highest point, the starting point or the finishing point.

For example

Lowest point - A swing or similar

Highest point - a satellite [rare]

Start point - projectile motion

Finish Point - roller coaster.
 
  • #37
Rayquesto said:
the height is the y direction between the heighest point and the lowest point. does that make sense?

On in proper description: The h value [change in height] is the difference between highest point and lowest point.
 

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