Thermal physics How would I go about this one?

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Homework Help Overview

The problem involves calculating the maximum increase in temperature of lead shot placed in a cardboard tube when inverted multiple times. It relates to concepts in thermal physics, specifically the conversion of gravitational potential energy to thermal energy.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to identify the relevant equations and concepts, expressing uncertainty about how to start the problem. Some participants suggest focusing on the conversion of gravitational potential energy to heat energy and using the appropriate equations to find the temperature change.

Discussion Status

Participants are actively discussing the calculations involved, with one participant attempting to apply the gravitational potential energy formula and the heat transfer equation. There is an ongoing exploration of the calculations and whether the approach taken is correct, with no explicit consensus reached yet.

Contextual Notes

Participants note the potential confusion regarding the specific values used in calculations, such as the specific heat capacity of lead, and the implications of multiplying by the number of repetitions in the experiment.

benji
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Two hundred grams of lead shot is placed in a 1.5-m-long cardboard tube, which is closed at both ends. If the tube is in a vertical position and then quickly inverted, the shot falls through the length of the tube. If this is done 50 times in succession, what is the maximum increse in temperature of the shot?

We just started this stuff and I'm not too good at it, I was able to figure out most of my homework from a thread I posted earlier today and a lot of reading, but this question still stumps me... If you could just get me started on which equation to use, what the concept is behind it, I'm sure I'll be able to figure out the rest from there.

Thanks!
 
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benji said:
We just started this stuff and I'm not too good at it, I was able to figure out most of my homework from a thread I posted earlier today and a lot of reading, but this question still stumps me... If you could just get me started on which equation to use, what the concept is behind it, I'm sure I'll be able to figure out the rest from there.

Thanks!

Hint: Gravitational potential energy is being converted to heat! Find out the how much grav. potential energy is converted to heat energy, and then find out the temperature change.
 
Okay, so I used Ug=mgh [Ug=.2(9.8)(1.5)] and I go 2.94J. Now I need to put that into the equation Q=mc(deltaT). So can I just use Ug=Q?

2.94=.2(29)(deltaT)?

I don't think this is right because I get .5C.

EDIT: Erm wait... I forgot to multiply that by 50... Now I have 25C. This could be right, did I do everything correctly?)
 
Last edited:
benji said:
Okay, so I used Ug=mgh [Ug=.2(9.8)(1.5)] and I go 2.94J. Now I need to put that into the equation Q=mc(deltaT). So can I just use Ug=Q?

2.94=.2(29)(deltaT)?

I don't think this is right because I get .5C.

EDIT: Erm wait... I forgot to multiply that by 50... Now I have 25C. This could be right, did I do everything correctly?)


It looks like it... :smile:

Daniel.

PS.That 29J Kg^{-1}K^{-1} looks terribly small...
 

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