Problem $3(40$ pts $)$: Trusses: determinacy &c method of joints. For the trusses

below:

$($i$)$ Calculate their determinacy $(6$ pts$)$

$($ii$)$ For the determinate truss only, generate the FBD $(4$ pts$)$

$($iii$)$ Solve for its reactions $(10$ pts $)$ and perform one validation $(5$ pts $)$

$($iv$)$ Find the forces in all its members using the Method of joints $(15$ pts $).$