Final answer:
The change in the balloon air's internal energy is found using the first law of thermodynamics equation ΔU = Q - W, where Q is the heat absorbed and W is the work done by the system. By substituting the given values (Q=77.3 J and W=37 J), we calculate the change in internal energy to be 40.3 J.
Step-by-step explanation:
The change in the balloon air's internal energy can be calculated using the first law of thermodynamics, which states that the change in the internal energy (ΔU) of a system is the sum of the heat (Q) added to the system and the work (W) done by the system. In this case, the balloon air does work while expanding and also absorbs heat from a heat source. The work done by the gas (on the surroundings) is positive, and the heat absorbed is also positive, according to the sign convention used in physics.
The formula to find the change in internal energy is:
ΔU = Q - W
Here,
- The heat absorbed by the balloon air, Q, is 77.3 J.
- The work done by the balloon air, W, is 37 J.
Plugging in the values, we get:
ΔU = 77.3 J - 37 J
ΔU = 40.3 J
Therefore, the change in the balloon air's internal energy is 40.3 J.
This energy change represents the net effect of heat absorption and work done during the expansion of the hot air in the balloon. The problem involves concepts from thermodynamics, specifically the workings of a hot air balloon, which is part of physics.