In physics, a force is any influence that causes an object to undergo a certain change, either concerning its movement, direction, or geometrical construction. It is measured with the SI unit of newtons and represented by the symbol F. In other words, a force is that which can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate, or which can cause a flexible object to deform. Force can also be described by intuitive concepts such as a push or pull. A force has both magnitude and direction, making it a vector quantity.
The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional the mass of the object. As a formula, this is expressed as:
where the arrows imply a vector quantity possessing both magnitude and direction.
Related concepts to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque which produces changes in rotational speed of an object. Forces which do not act uniformly on all parts of a body will also cause mechanical stresses, a technical term for influences which cause deformation of matter. While mechanical stress can remain embedded in a solid object, gradually deforming it, mechanical stress in a fluid determines changes in its pressure and volume.
Read more about Force: Development of The Concept, Pre-Newtonian Concepts, Newtonian Mechanics, Descriptions, Fundamental Models, Non-fundamental Forces, Rotations and Torque, Kinematic Integrals, Potential Energy, Units of Measurement
Other articles related to "force":
... The SI unit of force is the newton (symbol N), which is the force required to accelerate a one kilogram mass at a rate of one meter per second squared, or kg·m·s−2 ... The corresponding CGS unit is the dyne, the force required to accelerate a one gram mass by one centimeter per second squared, or g·cm·s−2 ... foot-pound-second English unit of force is the pound-force (lbf), defined as the force exerted by gravity on a pound-mass in the standard gravitational field of 9.80665 m·s ...
... The life force was a combined clock and progress meter used to track the energy status of the dungeoneer (the main contestant) ... too long (Treguard would often tell the team "You're wasting Life Force"), taking "damage" through being attacked by monsters or obstacles, taking the ... In the first five series, the life force was a computer animated image of an adventurer wearing a helmet ...
... A fluid flowing past the surface of a body exerts surface force on it ... Lift is the component of this force that is perpendicular to the oncoming flow direction ... It contrasts with the drag force, which is the component of the surface force parallel to the flow direction ...
... cell in the mid-latitudes with air being deflected by the Coriolis force to create the prevailing westerly winds ... the full extent of the large scale interaction of pressure gradient force and deflecting force that in the end causes air masses to move along isobars was understood ... By 1912, this deflecting force was named the Coriolis effect ...
... crown mounted on a circle featuring the words Royal Australian Air Force, beneath which scroll work displays the Latin motto (shared with the Royal Air Force) Per Ardua Ad Astra ...
Famous quotes containing the word force:
“Mountains are to the rest of the body of the earth, what violent muscular action is to the body of man. The muscles and tendons of its anatomy are, in the mountain, brought out with force and convulsive energy, full of expression, passion, and strength.”
—John Ruskin (18191900)
“Like a kick in the butt, the force of events wakes slumberous talents.”
—Edward Hoagland (b. 1932)
“For those parents from lower-class and minority communities ... [who] have had minimal experience in negotiating dominant, external institutions or have had negative and hostile contact with social service agencies, their initial approaches to the school are often overwhelming and difficult. Not only does the school feel like an alien environment with incomprehensible norms and structures, but the families often do not feel entitled to make demands or force disagreements.”
—Sara Lawrence Lightfoot (20th century)