Question

Exercises
How does the force of gravitation between two objects change
when the distance between there is reduced to half ?
2. Gravitational force acts on an objects in proportion to their
masses. Why then a heavy object does not fall faster than
a light object?
3. What is the magnitude of the gravitational force between
the earth and a 1 kg object on its surface? (Mass of the
earth is 6 x 10 kg and radius of the earth is 6.4 x 109 m.)
4. 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?
5. If the moon attracts the earth. why does the earth not move
towards the moon?
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Answer 1

Answer:

Explanation:

(1)

The force of gravitation between two objects is inversely proportional to the square of the distance between them therefore the gravity will become four times if distance between them is reduced to half.

(2)Answer: All objects fall on ground with constant acceleration, called acceleration due to gravity (in the absence of air resistances). It  isconstant and does not depend upon the mass of an object. Hence, heavy objects do not fall faster than light objects

(3)Given :       Mass of earth    M=6×10 24  kg

                  Mass of object    m=1 kg

                 Radius of earth       R=6.4×10

6 m

Force of gravitation between them, F=

R 2GMm

F=(6.4×10 6 ) 26.67×10 −11 ×(6×10 24 )×1 =9.77 N

(4) According to the universal law of gravitation, two objects attract each other with equal force but in opposite direction. Therefore, the earth attracts the moon with the same force as the moon attracts the earth

(5)

Answer: The Earth and the moon experience equal gravitational forces from each other. However, the mass of the Earth is much larger than the mass of the moon. Hence, it accelerates at a rate lesser than the acceleration rate of the moon towards the Earth. For this reason, the Earth does not move towards the moon.