what is the mass of a 1000N man on earth?

2 answers

is it 100 kg (mass)
You're almost there, but g=9.8 and not 10 m/s².

Weight = mg where g=9.8 m/s² on earth.
So a weight of 1000N results from a mass, m, where
m=weight/g
=1000/9.8
=102 kg.