A student wants to model the physical weathering of rock. Which activity could the student perform? A. Place several cookies in a box, and then shake the box.

B. Place ice cream in a bowl, and then watch it melt.

C. Place drops of acid on chalk, and then observe the chemical reaction.

D. Place a paper boat in a ditch, and then use water from a hose to make it sail away.

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.