# What is Force?

Force refers to interactions that result to change in motion of any given object. The interactions may either be physical in nature or purely non-physical. A force that results from interactions that are not physical in nature is referred to as action-at-a-distance. Such include magnetic, electrical and magnetic force. Forces that result from interactions that are physical are known as contact forces. These include tension, spring, frictional and air resistance force. Force causes a shift in the velocity of an object that has mass including causing movement from its initial state of rest.

Measuring Force

Force may be defined using intuitive ideas such as pull or push. It has both direction and magnitude which makes it a vector quantity. A device known as force meter is used to measure force. Essentially, the newton’s SI unit is used to measure force and it is represented using the N symbol. In its original state, the Newton’s law implies that net force that acts on an object is equivalent to the change in momentum over time. This means that if an object’s mass is constant, its acceleration is directly proportional to net force that acts on it. It is also in the same direction of the force and it is inversely proportional to an object’s mass.

Concepts of Force

Force is not anything that can be seen or touched. Rather, its actions can be seen. Other concepts related to force are thrust that leads to an increase in an object’s velocity, drag which reduces an object’s velocity and torque which generates a shift in an object’s rotational speed. Where the body is extended, every section applies force on adjacent areas and the distribution of this force throughout the entire body is referred to as mechanical stress. Pressure is one of the common kinds of stress. Stress leads to deformation of solid matters or flow in liquids.