Thermodynamics: Calculating Energy Change for a Swimmer
What are the values of ΔE, W, and Q for a swimmer after a workout?
A swimmer does 430 kJ of work and gives off 170 kJ of heat during a workout.
Answer:
The values of ΔE, W, and Q for the swimmer after a workout are as follows:
ΔE = 260 kJ, W = 430 kJ, Q = 170 kJ
Final answer: In this problem, we use the first law of thermodynamics to calculate the change in internal energy (ΔE) of the swimmer after a workout. The work done (W) by the swimmer is 430 kJ and the heat given off (Q) by the swimmer is 170 kJ. Thus, the values are ΔE = 260 kJ, W = 430 kJ, and Q = 170 kJ respectively. The correct option is A).
Explanation: The question aims to find the values of ΔE, W, and Q for a swimmer after performing a workout. Here, W refers to the work done by the swimmer, which is given as 430 kJ. Q is the heat given off by the swimmer during the workout, given as 170 kJ.
Considering the first law of thermodynamics, ΔE internal = Q - W, where ΔE internal refers to the change in the internal energy of the system. Substituting the given values in this formula, ΔE (change in internal energy) = Q (heat given off) - W (work done) = 170 kJ - 430 kJ = -260 kJ.
Since the negative sign indicates that the system (swimmer) is losing energy, the correct answer is ΔE = 260 kJ, W = 430 kJ, Q = 170 kJ.