Impulse is defined as the change momentumģ. An example below of a car moving from right to left and the force due to air resistance pushing the car to the right.1. Air Resistance ForceForce due to air that tends to oppose any movement of an object in air.The forces of action and reaction have equal magnitude. Force of reactionThe reaction to air rushing down out of a balloon is the balloon moving upward.It may or may not have the same direction at different points of the string. The main characteristic of a tension is that it has the same magnitude at every point of the string, neglecting the mass of the string. Is a force transmitted by means of a flexible object such as a string, rope. A kinetic force of friction is exerted on an object that is in motion. The static force of friction is exerted on an object that tries to move. There are two types of force of friction: static and kinetic. In general, a force of friction opposes the motion of objects. Force of FrictionA force of friction is exerted by one object on another as one them moves or tries to move relative to the other.The table exerts a normal force N on the box. Example of a box on a table shown in the figure below. Normal ForceThe normal force is the force exerted by an object onto another object when in contact.Two forces of equal magnitude and opposite direction acts on each of the magnets in the figure below. Magnetic ForceIt is the force exerted on a magnet that is located in a magnetic field.Two forces of equal magnitudes and opposite direction act on two charges of different signs in the figure below. Electric Force on a ChargeIt is the force exerted on a charge that is located in an electric field.It is also called the weight of an object. This force is due to the gravitational field of the earth. Gravitational ForceIt is the force exerted by the earth on any object with a mass.A person that is pushing a box, is applying an external force on the box. Applied External ForceAny force applied to an object externally by another object, human or animal.Ĭlassification of Forces A force can be put in one of the two classes: Forces with contact and forces at a distance.Ī) Examples of forces with contact 1) The force exerted by person to push a trolleyĢ) The force (tension) exerted by a string on a suspended objectģ) The force exerted by the ground on a table in a room (normal force)ī) Examples of Forces at a distance (also called field forces) 1) The force exerted by a planet (Earth for example) on any object with a mass.Ģ) The force exerted by an magnet on another magnet.ģ) The electric force exerted by an electric charge on another electric charge. Therefore, the newton (N) is the magnitude of the force applied to an object of a mass of 1 Kg in order to acquire an acceleration of 1 m/s 2. Action and reaction forces acts on different objects and have equal magnitudes.Ī force is represented mathematically by a vector because both magnitude and direction are important to describe the force.
Forces are used to push or pull stationary objects, to stop moving objects, to change direction of moving objects.įorces always exist in pairs: a force of action and a force of reaction (third law of Newton).
This interaction may be at a distance or through contact. The weight of an object is the force of attraction that the earth exerts on this object. You need to exert a force to pull a box on the floor. A force is a vector quantity: its has a magnitude and a direction. What are Forces in Physics? A force describes, quantitatively, the interaction between two objects.
0 kommentar(er)
