forças

Forças is a term used in physics to denote interactions that cause changes in motion or shape. In physics, a force is a vector quantity that can cause an object with mass to accelerate. The SI unit is the newton (N), defined as a kilogram meter per second squared. According to Newton's second law, the net force acting on an object equals the product of its mass and its acceleration (F = ma). The acceleration is in the direction of the net force.

Forces can be contact forces, arising from physical contact (friction, tension, normal force, air resistance, applied force), or non-contact forces (gravitational, electrical, magnetic). The four fundamental interactions are gravitational, electromagnetic, strong nuclear, and weak nuclear, each acting at different ranges and scales. Any force is part of a system of forces, with the net force obtained by vector summation. In many problems, forces are analyzed using free-body diagrams to apply equilibrium conditions (net force zero implies rest or constant velocity) or dynamics equations to determine motion.

In practical terms, the concept of force underpins a wide range of disciplines, including engineering, biomechanics, astronomy, and materials science. It also provides the framework for designing structures, vehicles, and mechanisms, predicting how objects will respond to loads, torques, and interactions with fields.

In Portuguese, Forças can also refer to the armed forces, collectively known as Forças Armadas or simply Forças, encompassing branches such as the Army, Navy, and Air Force. The term is commonly used in contexts of national defense and security.