Ch. 10 Gravitation

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                               Ch.10 - Gravitation

Q1. How does the force of gravitation between 2 objects change when the distance between them is reduced to half?

A1. The masses of the 2 objects are M and m
       Distance = r/2
       Force = GMm/ (r/2)^2
                 = GMm/ (r^2/4)
                 = 4GMm/ r^2
Q2. Gravitational force acts on all objects in proportion to their masses. Why then a heavy object does not fall faster than a light object?

A2. The acceleration on the objects does not depend on their masses. The acceleration due to gravity is same on all objects. Thus ideally, a heavy object and light object fall at the same time, but in real life situations, heavy objects fall faster due to the variation in the effect of air resistance on a heavy object and a light object.

Q4. The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force that is greater or smaller or the same as the force with which the moon attracts the earth? Why?

A4. The earth attracts the moon with an equal force as F=GMm/r^2 and also because of Newton's 3rd law of motion.

Q5. If the moon attracts the earth, why does the earth not move towards the moon?

A5. The moon attracts the earth but the earth does not move towards the moon because the force exerted by the moon is very less as compared to the force exerted by the earth due to its smaller mass. Thus the acceleration produced by the moon's gravitational force on the earth is very less (negligible) and the earth does not move towards the moon.

















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