#4 - I guessed a torsional load but I see what it is now - a cantilever structure and you’re only asking about vertical movement, not rotational. I’m a hobby builder but was a bio major so I had to teach myself truss analysis. I’m always imagining some type of beam or truss and rearranging the load or members to see what happens - same stuff as your channel.
*4) Insufficient information For all of them! becasue there are no dimensions given or fixed/rotatable connections are unclear!* I ofcourse asumed these things and got everything right!
