Consider a monopropellant rocket designed to generate a thrust of 100000 N for 30 s. The specific impulse is 200 s, and the chamber pressure is 3 MPa. The specific gravity of the monopropellant is 1.008. A pressurized gas system (at initial pressure of 10 MPa and initial temperature of 300 K) with Helium (molar mass 4, specific heat ratio 1.67) is used for the propellant feed. What is the minimum volume of the gas tank required for the adiabatic expansion of the HPG?What is the corresponding mass of the pressuring gas?

An external consultant recommends that a plant installs a bank of capacitors for power factor correction. this will reduce the peak electrical demand charges by an average of 93 kw every month. the plant current pays $13 per kw in peak demand charges. the capacitor bank will include 223 kw of fixed capacitors, and 183 of variable capacitors. the fixed capacitors cost $59 per kw, and the variable capacitors will cost $65 per kw. the consultant charges 21% of the equipment costs to install the capacitors. because this project will reduce the demand for the electric utility, they are prepared to provide a one-time rebate of $42 per kw of reduced demand. what is the simple payback period for this project (in years)?