Thermal physics How would I go about this one?

AI Thread Summary
The discussion revolves around calculating the maximum temperature increase of lead shot after being dropped through a cardboard tube. The key concept is the conversion of gravitational potential energy to heat energy, using the equation Ug = mgh to find the energy. The user initially calculates the gravitational potential energy as 2.94 J and attempts to relate it to heat using Q = mc(deltaT). After realizing the need to multiply by the number of drops, they arrive at a potential temperature increase of 25°C. The conversation highlights the importance of correctly applying physics equations to solve thermal energy problems.
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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