Question 3 (10 points): A plastic beam of square cross section 30 mm 30 mm (see figure) is simply supported with span length L = 320 + UV in mm, where UV are the last two digits of your student number. A point load P = 450 N is placed at the midpoint of the beam. Calculate the maximum bending stress in the plastic. Hint: The maximum bending moment is at the midpoint of the beam. 30 mm 30 mm L