External force

Definition

An external force is any force that originates from outside a system and influences the motion of objects within that system. It can cause changes in velocity, direction, or state of an object's motion.

5 Must Know Facts For Your Next Test

1. External forces are responsible for acceleration according to Newton's Second Law of Motion: $F = ma$.
2. Gravitational force, friction, and applied forces are common examples of external forces.
3. External forces can be contact forces (e.g., friction, tension) or non-contact forces (e.g., gravity, electromagnetic).
4. The net external force acting on a system determines the system's overall acceleration.
5. In free-body diagrams, all arrows representing forces acting on an object must include external forces.

Review Questions

Related terms

Net Force:

The total force resulting from the vector sum of all individual forces acting on an object.

Free-Body Diagram:

A graphical representation used to visualize the applied forces, moments, and reactions on a body in a given condition.

Newton’s Second Law of Motion: $F = ma$, which states that the acceleration of an object is directly proportional to the net force acting upon it and inversely proportional to its mass.