Gravity has no effect on mass, and mass doesn't change, no matter where you are.
40 kilograms is 40 kilograms ... On Earth, on the moon, or floating "weightless" on your way from one to the other.
It's Mass will remain 40 kilo because mass is amount of matter in an object which does not change. However, weight will and its weight on the moon wi0l be about 65.9 Newtons
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