In a period of 0.9 s, 5.0  1023 nitrogen molecules strike a wall of area 7.8 cm2. If the molecules move at 330 m/s and strike the wall head on in a perfectly elastic collision, find the pressure exerted on the wall. (The mass of one N2 molecule is 4.68  10-26 kg.)

If you blow a thin stream of air with a speed of 7.2 m/s out of your mouth, what is the overpressure in your mouth? Assume that the speed of the air in your mouth is (nearly) zero.

In a period of 1.2 s, 5.0  1023 nitrogen molecules strike a wall of area 8.5 cm2. If the molecules move at 285 m/s and strike the wall head on in a perfectly elastic collision, find the pressure exerted on the wall. (The mass of one N2 molecule is 4.68  10-26 kg.)

In 2085, your company wins a contract to deliver oxygen to several asteroid-based habitats from another asteroid with plenty of oxygen locked up in ice. Since there is no drag in space, the size of the oxygen containers is not an issue, and the most economical method turns out to be to enclose about 6 x 105 kilograms of cold but gaseous oxygen at about half atmospheric pressure in a Mylar sphere 100 m in diameter. To the sphere, you have strapped a small rocket engine. While the engine is firing, the engine presses into the sphere roughly 10 meters, like a finger pushing in on a balloon, as the sphere accelerates. The engine exerts a constant thrust until the sphere reaches its interasteroidal cruising speed of 100 m/s. The sphere travels about 5.0 km while the engine is firing. What fraction of the energy the rocket engine has given to the sphere ends up as internal energy in the gas just before the engine shuts off?