Space frame ABCD is clamped at $A,$ except it is free to translate in the $x$ direction. There is also a

roller support at $D,$ which is normal to line CDE. A triangularly distributed force with peak

intensity $q_0=75\frac{N}{m}$ acts along $AB$ in the positive $z$ direction. Forces $P_x=60N$ and $P_z=45N$ are

applied at joint $C,$ and a concentrated moment $M_y=120Nm$ acts at the mid$-$span of member $BC.$

$($a$)$ Find reactions at supports A and $D.$

$($b$)$ Find internal stress resultants $N,V,T,$ and $M$ at the mid$-$height of segment $AB.$