Key Concepts A field is a region in space where one object can exert an influence on another object at a distance. A force is a push or pull on an object. A force is applied by one field acting on another similar field. A force applied to an object has a tendency to change the shape or the motion of an object.
Force is a vector quantity.
The SI fundamental unit for mass is the kilogram. The mass of an object is independent of gravitational field strength. Mass can be determined on an equal arm balance, by making comparisons against standard masses. At the same place in an external field, two objects with the same mass will have the same weight. Weight is the force that a gravitational field exerts on an object.