Activity 10.3 Class 9 Science Gravitation

Activity 10.3 Class 9 Science Gravitation Chapter 10

What activity asks?

Activity 10.3 asks us to drop a piece of paper and stone from some height and see which reaches the ground first. The activity also asks us to do the same thing in a vacuumed glass.



The stone reaches fast while paper arrives at the bottom late.


We all know that earth attracts all the object with the force proportional to the mass of the object.

F= GMm/R2

(Where G is the universal gravitational constant; M is the mass of the earth; m is mass of the object, and R is the radius of the earth.)




Thus we see that all the body falls with the same acceleration. We call this Acceleration due to gravity (g). Its value is 9.8m/s2.

But this does not happen in reality. Other forces come into play in a free fall. For example Friction due to air. Light objects like paper have a higher surface area. They offer higher resistance to the air; while the stone is heavy with a small source area. Stone offer lower friction with the air. As a result, when we fall paper and stone at the same time, stone reaches the ground fast.

A glass from which air is drawn out does not offer any resistance whether it is a stone or a paper or something else. As a result, all the objects fall at the same speed and reach the bottom simultaneously.


Next: Activity 10.4 Class 9 Science Gravitation.

See also: Activity 10.2 Class 9 Science Gravitation.


Ref: Chapter 10.

Activity 10.3 Class 9 Science Gravitation Chapter 10


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