Calculate the change in the internal energy of the engine.

Question

An automobile engine provides 528 Joules of work to push the pistons and generates 2122 Joules of heat that must be carried away by the cooling system.

Calculate the change in the internal energy of the engine.

 E =  Joules

Answer 1

∆W = -528 J (negative sign because the system is doing work)

∆Q = -2122 J (negative because heat is released by the system)

According to the 2nd law of thermodynamics, ∆U = ∆Q + ∆W where ∆U is the change in internal energy and ∆Q and ∆W are the change in heat and work respectively.

∆U = -528 J + -2122 J = -2650 J