Halliday, Resnick & Walker — Temperature, Heat, and the First Law of Thermodynamics: Problem 50

A lab sample of gas is taken through cycle $abca$ shown in the $p-V$ diagram of Fig. 18.20. The net work done is $+1.2 \text{ J}$. Along path $ab$, the change in the internal energy is $+3.0 \text{ J}$ and the magnitude of the work done is $5.0 \text{ J}$. Along path $ca$, the energy transferred to the gas as heat is $+2.5 \text{ J}$. How much energy is transferred as heat along (a) path $ab$ and (b) path $bc$?