Find the pressures Pд and PB at surfaces A and B in the tube, respectively. ○ Pgas, Patm O Patm, Patm PA, PB = O Pgas, Pgas +Patm OPgas, Pgas O Pgas +Patm, Patm Peas mercury A B 12

(a) Given that air is 21% oxygen, find the minimum atmospheric pressure that gives a relatively safe partial pressure of oxygen of 0.16 atm. (b) What is the minimum pressure that gives a partial pressure of oxygen above the quickly fatal level of 0.06 atm? (c) The air pressure at the summit of Mount Everest (8848 m) is 0.334 atm. Why have a few people climbed it without oxygen, while some who have tried, even though they had trained at high elevation, had to tum back?

A rock with a mass of 540 g in air is found to have an apparent mass of 342 g when submerged in water. (a) What mass of water is displaced? (b) What is the volume of the rock? (c) What is its average density? Is this consistent with the value for granite?

A car engine moves a piston with a circular cross-section of 73000.002cm in diameter a distance of 3.2500.001cm to compress the gas in the cylinder. (a) By what amount is the gas decreased in volume in cubic centimeters? (b) Find the uncertainty in this volume.