A chemical rocket is used for launch into earth orbit. The combustion stagnation temperature is 3000K. The molecular weight of the combustion products is 26. The gases expand isentropically as an ideal gas mixture with specific-heat ratio of 1.2. The area ratio Ae/A* of the nozzle is 20, and the throat diameter is 0.1m. Determine: a. The stagnation pressure if the expansion is correct at sea level
b. The rocket thrust at sea level, 15- km, 30km, and 60km altitude.

Tom is having a problem with his washing machine. he notices that the machine vibrates violently at a frequency of 1500 rpm due to an unknown rotating unbalance. the machine is mounted on 4 springs each having a stiffness of 10 kn/m. tom wishes to add an undamped vibration absorber attached by a spring under the machine the machine working frequency ranges between 800 rpm to 2000 rpm and its total mass while loaded is assumed to be 80 kg a) what should be the mass of the absorber added to the machine so that the natural frequency falls outside the working range? b) after a first trial of an absorber using a mass of 35 kg, the amplitude of the oscillation was found to be 10 cm. what is the value of the rotating unbalance? c) using me-3.5 kg.m, find the optimal absorber (by minimizing its mass). what would be the amplitude of the oscillation of the absorber?