Gravitation
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Question : 13
Total: 25
How will you ‘weigh the sun’, that is estimate its mass? The mean orbital radius of the earth around the sun is 1.5 × 10 8
Solution:
The gravitational force acting on Earth due to Sun is F =
, r →
Now, the centripetal force acting on the earth due to the Sun is
F c = M E r ω 2 = M E r
, ω →
Since, this centripetal force is provided by the gravitational pull of the Sun on the Earth, so,
∵ r = 1.5 × 10 8 k m
= 1.5 × 10 11 m ,
T = 365 d a y s
= 365 × 24 × 60 × 60 s
∴ M S =
≃ 2 × 10 30 k g .
Now, the centripetal force acting on the earth due to the Sun is
Since, this centripetal force is provided by the gravitational pull of the Sun on the Earth, so,
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