In physics, a force is an influence that causes an object to change its velocity, which means it can make the object start moving, stop moving, speed up, slow down, or change direction. It can also cause an object to change its shape or orientation. Force is essentially a push or a pull resulting from the interaction between objects
. Force is a vector quantity , meaning it has both magnitude (size) and direction. To fully describe a force, you need to specify both how strong it is and the direction in which it acts. The standard unit of force in the International System (SI) is the newton (N), where one newton is the force required to accelerate a 1-kilogram mass by 1 meter per second squared
. Newton's laws of motion provide the fundamental framework for understanding force:
- First law: An object remains at rest or moves at a constant velocity unless acted upon by a net external force.
- Second law: The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (F=maF=maF=ma).
- Third law: For every action force, there is an equal and opposite reaction force
Forces can be categorized as contact forces (like friction, tension, and normal force) or non-contact forces (like gravity and electromagnetic forces)
. In summary, force in physics is a push or pull that causes changes in an object's motion or shape, described by both magnitude and direction, and measured in newtons.
Key points:
- Force = push or pull causing change in motion or shape.
- Vector quantity: has magnitude and direction.
- Measured in newtons (N).
- Governed by Newton's laws of motion.
- Types include contact and non-contact forces.
This definition encompasses classical mechanics and is foundational for understanding how objects interact and move
