A person sitting inside an elevator performs a weighing experiment with an object of mass 50 kg. Suppose that the variation of the height y (in m) of the elevator, from the ground, with time t (in s) is given by y=8[1+sin(T2πt)], where T=40π s. Taking acceleration due to gravity, g=10m/s2, the maximum variation of the object's weight (in N) as observed in the experiment is _____