Question

The weight of an object is not constant. Why

Answer 1

Mass of an object is actually the amount of matter it contains and it would remain the same unless there is change in the amount of matter whereas weight of an object is the force on it due to gravity.. Consider an object with mass 1kg whose weight would be 9.81 N approx. on earth. It would be less in Mars due to variation in gravity. Weight of an object varies from place to place due to variation in gravity at different places. There are factors due to which acceleration due to gravity may vary . Like altitude, latitudes and even the spinning of our planet may vary acceleration due to gravity at different places on earth. Sometimes even geological factors account to change in value of acceleration due to gravity.
​​​​​Weight,W=Mass(m)*acceleration due to gravity(g).
since mass is constant
weight is proportional to g and varies with g.