Solution :
Given :
Height of the tower , h = 45 m
Weight of the weather vane, mg = 190 N
So the potential energy possessed by the weather vane is given by
E = m x g x h
where, E is potential energy
      m is mass
      g is acceleration due to gravity (taken as 10 m/s2)
      h is height
Therefore,
E = m x g x h
E = (mg) x h
E = 190 x 45
E = 8550 J