Contact and Field forces

Forces can be grouped into two categories; contact forces and field forces. Contact forces are due to direct physical contact between objects. For example, the restoring force from a spring to the attached mass. Field forces, however, act without the necessity of physical contact between objects and they depend on the presence of a “field” in the region of space surrounding the body under consideration. Since the mass is in Earth’s gravitational field, it feels a gravitational force; in other words, he has weight.

There is a spring with a circular body at the end of it. This body has its center marked with a C and two arrows pointing up and downwards from it. The arrow pointing up is labelled as restore force and the arrow pointing down is labelled as force of gravity.

Figure 1: The restoring force (contact force) and weight (field force) of a mass on a spring.