For the Maxwell viscoelastic model: a) Derive the differential equation for this model and use the differential equation to write the expressions for the case of stress relaxation and creep. b) Draw the predicted time vs. strain response for the case of creep, and the predicted time vs. stress response for the case of stress relaxation. c) Discuss whether the Maxwell model would be capable of accurately describing the creep and stress relaxation behaviors of a polymer.

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)?