$4\mathrm{.}2.$ A beam is subjected to a uniformly distributed load and has a maximum shear of $60$ kip at the face of its supports. The beam clear span is $30ft-0in.,b=12in,,d=24in.,f_c^{\text{'}}=4,000,$ and $f_{yt}=60,000.$ What is the shear at the critical section? What is the required spacing for #$3$ stirrups at the critical section?