Question

What is the relation between weight and mass?

Answer 1

 Mass and weight are two different quantities and one should not confuse one with he other. Firstly weight is a vector quantity and mass is a scalar and therefore invariant with respect to location. In fact it can be used as a measure of inertia. Weight is equal to the force of gravity acting on a body and does vary with a body's location (altitude, latitude and with the value of gravitational accelleration and so on). This difference can be understood by looking at their respective definitions. 
m(gravitational) = W/g and m'(inertial)= F/a 
A given body can be weightless (a reactionless state, to be exact) but it cannot be massless. 
Our weight on the moon, for example would be 1/6 that on the earth but our masses on earth or moon would be the same ant it would require the same force to accelerate us on the earth or the moon.............