Determine the required spacing of shear reinforcement over the span of a 28-in-wide and 18-in-deep beam with a clear span equal to 30 ft. 2 in. the beam suports a total factored uniformly distributed load of 5.0 kips/ft. Assume no. 4 U-stirrups wth 2 legs (grade 60) and normal weight concrete with f'c= 5 ksi. Also determine the distance after which minimum stirrups can be used.