AP Physics 2 - Thermodynamics

the change in internal energy of a closed system is due to heat added or removed from the system and/or work done on or by the system

△U=Q-W

process or change taking place at a constant temperature

process in which pressure is constant

a body whose mass is so large that, ideally, the temperature does does not change significantly when heat is exchanged

1. heat energy flows spontaneously from a hot object to a cold object but not vice versa

2. it is impossible to construct a heat engine that is 100% efficient, a heat engine can convert some heat into useful work, but the rest must be exhausted in waste heat

3. the entropy of an isolated system never decreases, it can only stay the same or increase

any process that occurs without heat gain or loss

e = 1 - Qc/Qh e = W/Qh

ideal engine, no energy loss due to internal friction, turbulence, etc.

process in which volume is constant

operate by removing heat from low temperature reservoir and exhausting the heat to a higher temperature reservoir, work is done

any device that changes thermal energy in to mechanical work

a device that does work(W) to take heat from low temperatures(QL) and delivers it to warmer areas(QH)

all processes are done so slowly that the whole process could be considered a series of equilibrium states so the whole process could be done in reverse with no magnitude, work done, or heat exchange/change

the degree of disorder in a system, no thermal energy to convert to work

universe would be in maximum disorder, all matter would be uniform, everything would be one temperature, all energy would go to thermal energy, no work could be done

thermal radiation is absorbed by atmospheric greenhouse gases and is re-radiated everywhere

heat output (QL) from every heat engine, this heat must then be absorbed by the environment

converts sunlight directly into electricity without the use of a heat engine, photo voltaic cells

study of energy transformation in natural processes and involves relations among heat, work, and energy