part i)

weight of the bar = mg = 9.81(80) = 784.8 N

It can be assumed that this weight acts at the center of the bar(8 m away from A or B)

using moment about B

where x = distance of normal force acting on the bar acting upwards at N from B = 16 - 6 = 10m

= reaction at N

therefore,

part(ii)

resolving forces vertically:

where R_M = reaction force action on the bar at M