Question

Why is the weight of the same object different on different plants

Answer 1

Because of gravitational force or upward force which is different on different planets....
It also varies from planets to moon....
Also the unit of force is Newton...

Answer 2

this is because every planet has different mass and universal law of gravity says that force produced or gravity is directly proportional to the product of mass of planet and that of person that is the reason weight of every object id different on every planet