Henry gets into an elevator on the 50th floor

[p14r]

Henry gets into an elevator on the 50th floor of a building and it begins moving at t=0.00 s. His apparent weight is shown over the next 36.0s


What is Henry's mass if his maximum apparent weight within the elevator is 900.0N?

so shouldn't it just be:
w = mg
m = w/g
= 900/9.8
= 91.84 kg

but I keep getting the answer wrong.

 

[gneill]

Can you identify on your graph where the maximum apparent weight occurs? How about his minimum apparent weight?

What do you suppose is happening with the motion of the elevator to cause these readings? Where would you expect to see his normal apparent weight?