Who was the first astronaut to step outside of the Apollo 11 spacecraft, saying the now famous words “one small step for man, one giant step for mankind” as he placed the American flag on the rocky terrain?
Buzz Aldrin
Michael Collins
Neil Armstrong
Yuri Gagarin

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.

What pressure difference is required between the ends of a 2.0-m-long, 1.0-mm-diameter horizontal tube for 40 c water to flow through it at an average speed of 4.0 m/s?