This theory, based on the everyday experience of how objects move, such as the constant application of a force needed to keep a cart moving, had conceptual trouble accounting for the behavior of projectiles, such as the flight of arrows. He distinguished between the innate tendency of objects to find their "natural place" (e.g., for heavy bodies to fall), which led to "natural motion", and unnatural or forced motion, which required continued application of a force. Aristotle believed that motionless objects on Earth, those composed mostly of the elements earth and water, were in their natural place when on the ground, and that they stay that way if left alone. In Aristotle's view, the terrestrial sphere contained four elements that come to rest at different "natural places" therein. Īristotle provided a philosophical discussion of the concept of a force as an integral part of Aristotelian cosmology. Analysis of the characteristics of forces ultimately culminated in the work of Archimedes who was especially famous for formulating a treatment of buoyant forces inherent in fluids. The mechanical advantage given by a simple machine allowed for less force to be used in exchange for that force acting over a greater distance for the same amount of work. Since antiquity the concept of force has been recognized as integral to the functioning of each of the simple machines. See also: Aristotelian physics and Theory of impetus Aristotle famously described a force as anything that causes an object to undergo "unnatural motion" : 2-10 : 79 High-energy particle physics observations made during the 1970s and 1980s confirmed that the weak and electromagnetic forces are expressions of a more fundamental electroweak interaction. Only four main interactions are known: in order of decreasing strength, they are: strong, electromagnetic, weak, and gravitational. The Standard Model predicts that exchanged particles called gauge bosons are the fundamental means by which forces are emitted and absorbed. With modern insights into quantum mechanics and technology that can accelerate particles close to the speed of light, particle physics has devised a Standard Model to describe forces between particles smaller than atoms. īy the early 20th century, Einstein developed a theory of relativity that correctly predicted the action of forces on objects with increasing momenta near the speed of light and also provided insight into the forces produced by gravitation and inertia. With his mathematical insight, Newton formulated laws of motion that were not improved for over two hundred years. Most of the previous misunderstandings about motion and force were eventually corrected by Galileo Galilei and Sir Isaac Newton. A fundamental error was the belief that a force is required to maintain motion, even at a constant velocity. In part, this was due to an incomplete understanding of the sometimes non-obvious force of friction and a consequently inadequate view of the nature of natural motion. Philosophers in antiquity used the concept of force in the study of stationary and moving objects and simple machines, but thinkers such as Aristotle and Archimedes retained fundamental errors in understanding force. In modern physics, which includes relativity and quantum mechanics, the laws governing motion are revised to rely on fundamental interactions as the ultimate origin of force, but the understanding of force provided by classical mechanics remains entirely satisfactory for many practical purposes. If these are not in equilibrium they can cause deformation of solid materials, or flow in fluids. In equilibrium these stresses cause no acceleration of the body as the forces balance one another. In an extended body, each part often applies forces on the adjacent parts the distribution of such forces through the body is the internal mechanical stress. The rotational version of force is torque, which produces changes in the rotational speed of an object. Types of forces often encountered in classical mechanics include elastic, frictional, contact or "normal" forces, and gravitational. The SI unit of force is the newton (N), and force is often represented by the symbol F.įorce plays a central role in classical mechanics, figuring in all three of Newton's laws of motion, which specify that the force on an object is equal to the product of the object's mass and the acceleration that it undergoes. Because the magnitude and direction of a force are both important, force is a vector quantity. The concept of force makes the everyday notion of pushing or pulling mathematically precise. In physics, a force is an influence that can cause an object to change its velocity, i.e., to accelerate, unless counterbalanced by other forces.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |