Question

3. Distinguish between. centripetal force and centrifugal force. Explain in what direction each force t acting and on what it is acting. 32 4. Calculate at what speed the earth would have to rotate in ordet that objects at the equator would have n weight. Assume the radius of the earth to be 6400 kilometers. What would be the linear speed of a point o the equator? What would be the length of a day (time from sunrise to sunset) under these conditions?

Answer 1

Radius of earth = 6400 km When the objects loses weight means mg = Mv^2/R g = v^2/R Therefore V = squareroot gR = squareroot 9.8 times 64 times 10^3 = 7.92 times 10^3 m/s So the linear speed of a point on the equation V = 7.92 times 10^3 m/s The length of the day. T = 2 pi R/V = pi times (6400 times 10^3 m)/7.92 times 10^3 = 2534.4 sec T = 42 min or 7 hour Centrifugal force is the force that is directed toward the centre of the circle and acts on the body in order to keep it moving in circular orbit. According the Newton�s Third law the reaction force, which is the centrifugal force is the body on the Restraining medium (The string in the case) with same magnitude and opposite direction to the centrifugal force.