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

[intenzxboi]

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..

 

[rock.freak667]

Think about conservation of energy.

 

[intenzxboi]

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

 

[cepheid]

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.

 

[intenzxboi]

mgd= delta q + KE?

 

[songoku]

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?

 

[songoku]

Sorry I'm late...
the last one is right

 

[cepheid]

mgd= delta q + KE?

Yes.

 

[intenzxboi]

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

So t = 4.98
does that look right?

 

[intenzxboi]

my other question is if i did it like that wouldn't the units for my answer be 4.98 kg/J = delta T ??

 

[songoku]

the number is right but not the unit. What is the unit for temperature?

 

[intenzxboi]

o0o got it C the kg and J cancels out

 

[intenzxboi]

thanks for all the help