The wing on an airplane, traveling at 100 mph, experiences both bending and torsion loading. This results in a normal stress (σxx = 22.3 ksi) and shear stress (τxy = 18.6 ksi) on the lower surface of the aluminum skin. Assume that the allowable strength for aluminum is (σ* = 50 ksi). It is observed that both stresses increase linearly with increasing aircraft speed. Similarly, both stresses decrease linearly with decreasing speed. What is the maximum safe aircraft speed such that (MS = +0.1) based upon the maximum strain energy of distortion criteria? (Units: mph)

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)?