An astronaut in a spacesuit on a spacewalk is a completely sealed system, with no matter lost or gained. In principle, the energy the astronaut uses will result in a decrease in mass. Suppose on a gentle spacewalk his metabolic power plus the power of the suit is 340 W. What is the change in mass, in kg, on a 1.0 hour spacewalk?

Because air contracts as it cools, the air pressure inside a freezer is typically lower than on the outside. why do ice cubes inside a freezer tend to shrink over time? a. the ice dissolves oxygen from the air, forming a denser crystalline matrix. b. the ice reacts chemically with carbon dioxide in the air, forming gaseous carbon compounds. c. the ice melts, and then the liquid freezes as ice crystals on the bottom of the freezer. d. the ice sublimes, and then the water vapor deposits as ice crystals on the sides of the freezer.