A motor produced 10kj of energy each second as mechanical work and lost 5kj as heat to the surrounding calculate the change in internal energy of the motor each second.

Answer 1

To calculate the change in internal energy of the motor each second, we can use the first law of thermodynamics, which states that the change in internal energy (ΔU) of a system is equal to the heat transfer (Q) into the system minus the work done (W) by the system: ΔU = Q - W.

In this case, the motor produces 10 kJ of energy each second as mechanical work (W = 10 kJ) and loses 5 kJ as heat to the surroundings (Q = -5 kJ, since it is lost from the system).

Plugging these values into the equation:
ΔU = Q - W
ΔU = -5 kJ - 10 kJ
ΔU = -15 kJ

Therefore, the change in internal energy of the motor each second is -15 kJ.