Heat with relation to work or energy

AI Thread Summary
To determine the heat generated from a collision, one must calculate the kinetic energy (KE) lost during the impact. This involves finding the initial potential energy (PE) and the KE just before the collision, assuming that most of the lost energy converts to heat. When an object comes to rest after a fall, all mechanical energy is eventually transformed into random thermal energy, along with some energy potentially lost to sound and light. A good estimate for the heat produced can be obtained by equating the initial PE to the heat generated. This method provides a straightforward approach to understanding energy transformation in collisions.
aglo6509
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Hello,
I know this seems silly to ask, but how could I figure out how much heat was given off when I know the force of an object hitting another?
 
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What's important is how much macroscopic kinetic energy is 'lost' in the collision, not the force involved.
 
So if I know the KE of the system I can find the heat?
 
aglo6509 said:
So if I know the KE of the system I can find the heat?
You need the amount of KE 'lost'. There are many kinds of energy other than 'heat' (random thermal energy), but you may be able to assume that most or all of the energy lost goes to 'heat'.
 
Doc Al said:
You need the amount of KE 'lost'. There are many kinds of energy other than 'heat' (random thermal energy), but you may be able to assume that most or all of the energy lost goes to 'heat'.

So if an object starts from rest 1/2 metre away from the object, I would first find Ug then KE right as it hits the object and assume all the lost energy is released as heat?
 
aglo6509 said:
So if an object starts from rest 1/2 metre away from the object, I would first find Ug then KE right as it hits the object and assume all the lost energy is released as heat?
If you drop something and it comes to rest, all the mechanical energy (PE + KE) is lost. Some might go to sound and light, but sooner or later it all becomes random thermal motion somewhere.

Just set the initial PE (measured from the final position) equal to the 'heat' for a good estimate.
 
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