At its core, a force is an interaction that changes the motion of an object. It’s not something you can hold in your hand, but it has real, observable effects. A force is a push or pull that acts upon an object as a result of that objects interactions with its surroundings. In this Lesson, The Physics Classroom differentiates between the various types of forces that an object could encounter. Force is a fundamental concept in Physics, driving changes in motion, direction, or shape of objects. Understanding the definition of force, its types, formulas, and real-world applications reveals its crucial role in natural phenomena and technology. The strength of a force is measured in newtons (N). There are four fundamental forces in physics. A force is always a push, pull, or a twist, and it affects objects by pushing them up, pulling them down, pushing them to a side, or by changing their motion or shape in some other way. The force on an object equals the object’s mass multiplied by its acceleration. When one object exerts a force on another object, the second object exerts an equal and opposite force on the first. The meaning of FORCE is strength or energy exerted or brought to bear : cause of motion or change : active power. How to use force in a sentence. Synonym Discussion of Force. Force is a vector quantity, as it has both magnitude and direction. The magnitude of a force represents its strength. The force can also cause a change in direction in the body to which it is applied. Two or more things must interact with each other for a force to be created. Force, in mechanics, any action that tends to maintain or alter the motion of a body or to distort it. The concept of force is commonly explained in terms of Isaac Newton’s three laws of motion. Because force has both magnitude and direction, it is a vector quantity. In physics, a force is an action that can cause an object to change its velocity or its shape, or to resist other forces, or to cause changes of pressure in a fluid. In mechanics, force makes ideas like pushing or pulling mathematically precise. A force is a push or pull that acts upon an object as a result of that objects interactions with its surroundings. In this Lesson, The Physics Classroom details that nature of these forces, discussing both contact and non-contact forces.