mass of the object = 1000 kg
height = 146
meter acceleration due to gravity = 9.8 m/s^2
but for easy calculation we will take acceleration due to gravity as
= 10 m/s^2
So for this ,
W = 1000 x 10 x 146
W = 1460000 J
W = 1.46 x 10^6 J
answer is = 1.46 x 10^6J