What is the change in temperature of a coin dropped from a building?

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Homework Help Overview

The problem involves a 5-g coin dropped from a 300-m building, reaching a terminal velocity of 45 m/s, and seeks to determine the change in temperature of the coin due to energy conversion during the fall.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the conservation of energy, questioning how potential energy relates to thermal energy and kinetic energy. There are attempts to formulate the relationship between these energies and the change in temperature.

Discussion Status

Some participants have provided guidance on the energy equations involved, while others are exploring the correct interpretation of energy conversion. There is a mix of agreement and differing opinions on the energy components before and after the coin is dropped.

Contextual Notes

Participants mention a lack of resources, such as textbooks, which may affect their understanding of the concepts involved. There is also a focus on ensuring the correct units for temperature change are identified.

intenzxboi
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Homework Statement



A 5-g coin is dropped from a 300-m building. If it reaches a terminal velocity of 45 m/s, and the rest of the energy is converted to heating the coin, what is the change in temperature (in °C) of the coin? (The specific heat of copper is 387 J/kg °C.)

I have no idea how to start the problem..
 
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Think about conservation of energy.
 
So...
Potential Energy initial = delta Q?

I don't have a physics book and the teacher pdf notes kinda suck can i get the formula for the thermal change in energy
 
intenzxboi said:
So...
Potential Energy initial = delta Q?

Nope. Not all of it is converted into heat. Obviously if the object starts at 0 m/s and ends up at 45 m/s, it has gained some kinetic energy too.
 
mgd= delta q + KE?
 
No
Total energy before the coin is dropped = total energy after it reaches terminal velocity
What is/are the energy/energies present before it is dropped?
What is/are the energy/energies present after it reaches terminal velocity?
 
Sorry I'm late...
the last one is right
 
intenzxboi said:
mgd= delta q + KE?

Yes.
 
(.005)(9.8)(300) = (5)(387)T + (.5)(.005)(45^2)

So t = 4.98
does that look right?
 
  • #10
my other question is if i did it like that wouldn't the units for my answer be 4.98 kg/J = delta T ??
 
  • #11
the number is right but not the unit. What is the unit for temperature?
 
  • #12
o0o got it C the kg and J cancels out
 
  • #13
thanks for all the help
 

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