A scientist pours grape juice on three identical white shirts. He then uses three different cleaning products on the shirts and measures how clean they
get. What is the independent variable in this experiment?
A. The color of the shirts
B. How clean the shirts get
C. The cleaning product used
D. The type of grape juice used

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.