Determine the $I_{NA},$ the maximum compressive stress in concrete $(f_c)$ and the maximum tensile stress in the steel $(f_s)$ of the simple beam as shown in Figure $3.$

Given: $f{c}^{\text{'}}=180ksc,$ steel bar grad SD$40,$ the modulus of rupture $=25ksc$

$($a$)$ If the beam is subjected to a positive bending moment of $1500kg-m(5$ point$)$

$($b$)$ If the beam is subjected to a positive bending moment of $5000kg-m(5$ point$)$

Figure $3$ Beam cross section