Chapter 18 - The Laws of Thermodynamics - Problems and Conceptual Exercises - Page 647: 57

(a) $19.7KJ$ (b) $54.2KJ$

(a) We know that $COP=\frac{Q_c}{W}$ We plug in the known values to obtain: $1.75=\frac{3.45\times 10^4}{W}$ $\implies W=1.97\times 10^4J=19.7KJ$ (b) As $Heat \space exhausted=Q_h=Q_c+W$ We plug in the known values to obtain: $Q_h=3.45\times 10^4+1.97\times 10^4=5.42\times 10^4J=54.2KJ$