In physics, when mass is defined using Newton's second law, it is the resistance of a body to acceleration by any force. A body with natural mass has inertia. According to the theory of gravity, mass is a multiplier (parameter) that also determines the magnitude of the gravitational interaction, and the mass of a body can be obtained from gravity, based on the equivalence principle. But mass and weight are different concepts. The weight can change according to which object is gravitationally affected and according to its position.