Answer:
Merely multiple the mass X gravitational attraction
On earth (F = M a) = 50 kg * 9.8 m/s^2 = 490 N
On the moon 50 kg * 1.6 m/s^2 = 80 N (apparent weight on moon)
On Mars 50 kg * 3.2 m/s^2 = 160 N
Treat the other item in the same manner.
