Centripetal and centrifugal forces

centripetal and centrifugal forces

1. Centripetal and Centrifugal Forces MADE BY - ANKITA

2. Centripetal Forces Sir Isaac Newton explained it as “the force by which objects are drawn, or in any way, towards a point as to a center. In Newtonian mechanics, the force of gravity provides the centripetal force for astronomical orbits. It is a real force that is necessary to keep an object moving in a curved path and that is directed inward toward the centre of rotation , exerted on the body by the external agencies like gravitational force, tension in the string etc. It acts both in Inertial and Non –inertial frame.

3. CONT.. The force needed by a body of  mass   m , to keep in a circular motion at a  distance   R , from the centre of a circle with  velocity   v , is the centripetal force  F c , where The direction of the force is towards the center of the circle of motion, and its magnitude and direction can both be derived from a consideration of Newton’s second law of motion

4. CONT.. In astronomy many stars, planets and disks of material move in circular orbits and require a force equivalent to the centripetal force to maintain their circular motion. This force is usually gravity. By balancing the gravitational and centripetal forces it is possible to obtain estimates of the mass within a given radius from the rotation curves of galaxies or accretion disks around supermassive black holes .

5. Examples of centripetal force The moon revolves around the earth is the example of centripetal force. The gravitational force of the earth provides the necessary centripetal force. Washing machine dryer: The dryer of the washing machine is basket spinner. It has a perforated wall having a large number of fine holes in the cylindrical rotor. The lid of the container is closed after putting wet clothes in it. When it spins at high speed, the water from wet clothes is forced out through these holes due to a lack of centripetal force.

6. Centrifugal Forces Centrifugal force is the apparent outward force on a mass when it is rotated. It is pseudo or fictitious force which cannot arise from gravitational force, tension etc.  The  centrifugal force  is a pseudo-force because if the centripetal force ceased for an object in circular motion, the centrifugal force the body is “feeling” would instantly disappear, and the object would travel tangentially to its line of motion. It only arises because the body is in a non-inertial frame of reference.

7. CONT. Centrifugal force is the apparent outward force on a mass when it is rotated. Since Earth rotates around a fixed axis, the direction of centrifugal force is always outward away from the axis, opposite to the direction of gravity at the equator; at Earth’s poles it is zero. (Centripetal force is the necessary inward force that keeps the mass from moving in a straight line; it is the same size as centrifugal force, with the opposite sign. Centripetal force is real; centrifugal force is just an apparent force .)

8. CONT.. The reaction of the centripetal force is called the centrifugal force. Explanation: Consider a stone which is tied to a string moving in a circle. The necessary centripetal force acts on the stone through the string that keeps it to move in a circle. According to Newton’s third law of motion, there exists a reaction of this centripetal force. The centripetal reaction that pulls the string outward is called centrifugal force.

9. Centripetal Vs Centrifugal                          Centripetal force Centrifugal force 1: It is the force which keeps the body to move in the circle.   1: It is the force which keeps the body away from the circle. 2: It is a real  force 2: It is a fictitious force. 3: Its direction is towards the center of the circle. 3: Its direction is away from the center of the circle. 4: It is observed in the inertial frame of reference. 4: It is not observed in the inertial frame of reference.