A sample of gas is taken through cycle abca shown in the p-V diagram of Figure 2. The net work done is +2.0 J. Along path ab, the magnitude of the work done is 4.0 J, the energy transferred to the gas as heat is +7.0 J. Along path ca, the energy transferred to the gas as heat is +3.0 J.
(a) What is the change in internal energy along path ab?
(b) How much energy is transferred as heat along path bc?