2C First Law of Thermodynamics Flashcards
mechanical work
the energy transferred to or from an object when a force is applied over a distance
what must happen in order to do work on an object
- a force must be applied
- the object must move in the direction of the force (e.g. firing a cannon)
mechanical work formila
W=Fd
how is heat used to do mechanical work
heat can be used to do mechanical work mainly through the expansion of fluids
what happens when a system gains thermal energy
the particles move faster, increasing the systems temperature and internal energy
- when heat is added to a fluid, it expands creating pressure. this pressure can push or pull components (e.g. pistons) in a system, resulting in mechanical work
1st law of thermodynamics
energy cannot be created or destroyed only transferred or transformed. = law of energy conservation
1st law of thermodynamics formula
delta/U= Q+W
delta/U= change in internal energy
Q= heat energy added or removed
W= work done on or by the system
-Q
heat out of the system
+Q
heat into the system
+W
work done on the system
-W
work done by the system
