Mass and Weight
\[m\]of a body is a measure of the 'amount of stuff' in a body.
\[W\]of a body is a measure of the force, specifically the force of gravity acting on a body.
Despite being different concepts, mass and weight are related at each point in space by the equation
\[g\]is the acceleration due to gravity at that point and is equal to about
\[9.8 m/s^2\]on the Earth's surface.
The above equation ignores all forces except the force of gravity. It would not be true for a charged particle in an electric field because the force would be at least partially electric, so would not be due solely to gravity.