Air in a balloon does 25 J of work while absorbing 81 J of heat. What is the change in internal energy?
Let U be the internal energy. Qin is the heat in and Wout is the work done.
The energy equation for a given constant mass is:
Change in U = Qin - Wout
In your case, that is 81 - 25 = ? Joules
56 J
To find the change in internal energy, we can use the equation:
ΔU = Q - W
Where:
ΔU is the change in internal energy
Q is the heat absorbed
W is the work done
Given:
Q = 81 J (heat absorbed)
W = 25 J (work done)
Let's plug in the values:
ΔU = 81 J - 25 J
ΔU = 56 J
Therefore, the change in internal energy is 56 J.
To find the change in internal energy, we need to consider the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system:
Change in internal energy = Heat added - Work done
Given that the balloon absorbs 81 J of heat, and does 25 J of work, we can substitute these values into the equation to find the change in internal energy:
Change in internal energy = 81 J - 25 J
Change in internal energy = 56 J
Therefore, the change in internal energy is 56 J.