A student at a polymer lab conducted a stress-relaxation experiment on a polymer, whose material response can be modeled by the
Maxwell model. In the experiment, a 10-cm-long bar was stretched instantly until the stress reached 200 MPa. After 2 min, the measured stress in the bar was 160 MPa. a) Calculate the relaxation time constant of the polymer. b) If the initial stress was reached by stretching the bar by 16 mm, what is the viscosity of the dashpot in the Maxwell model
It can't be less than 250 N or the cart wouldn't move at all. That means there is only 1 answer. It's between not enough info or 250 N. The answer is 250 N. If it was any more, there would be acceleration.
