Q1: Why does the presence of solid particles in the exhaust of most solid-fuel rockets decrease the overall exhaust velocity? Q2: Why do big rockets have pump-fed propellant feed systems, and not pressure-fed ones? Q3: In rocket engine design, with few exceptions (e.g. oxidizer-rich staged combustion) we like to keep the oxidizer part of the propellant inflow at a low temperature all the way up to the point where it flows into the combustion chamber (this is why fuel is usually used for cooling the thrust chamber). Why do we do this? Q4: In standard liquid propellant rockets, which fuel yields the highest specific impulse? Q5: What is the most common monopropellant used in liquid rocket engines?