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During a solar eclipse,the moon(of mass 7.36x10^22kg), Earth(of mass 5.98x10^24kg), and...

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lala25 | Student, Undergraduate | (Level 2) eNoter

Posted November 23, 2009 at 9:41 PM via web

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During a solar eclipse,the moon(of mass 7.36x10^22kg), Earth(of mass 5.98x10^24kg), and Sun(of mass 1.99x10^24) lie on the same line,

with the moon between Earth and the Sun.

What gravitational force is exerted on the moon by the Sun? The universal gravitational constant is 6.673 x 10^-11 N times m^2/ kg^2, the Earth-moon distance is 3.84 x 10^8 m, and the Earth-Sun distance is 1.496 x 10^11 m. Answer in units of N.

What gravitational force is exerted on the moon by Earth? Answer in units of N.

What gravitational force is exerted on Earth by the Sun? Answer in units of N.

5 Answers | Add Yours

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pohnpei397 | College Teacher | (Level 3) Distinguished Educator

Posted November 23, 2009 at 11:28 PM (Answer #1)

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The force exerted by the moon on the Earth is

2.98 x 10^31 joules.

The gravitational force exerted by the Earth on the Sun is

3.58 x 10^23 joules

These figures are derived by using the following equation for gravitational force:

Fg = (Gm1m2)/r^2

where G is the universal gravitational constant, m1 and m2 are the masses of the objects, and r is the distance that separates their centers.

I should note that I am not using the number you provided for the mass of the Sun because you seem to have mistakenly stated the wrong power for it.  It is raised to the 30th power, not to the 24th.  My calculation is based on that number and I provide a link below to a page showing that as the correct mass of the Sun.

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neela | High School Teacher | (Level 3) Valedictorian

Posted November 24, 2009 at 1:09 AM (Answer #2)

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We use the the relation of law of universal gravitational law of Newton to find the force between the two bodies of mass M and m sepated by a distance R.

F= GMm/R^2, G is the gravitational constant, M and m are the masses of the bodies.

Between Earth and sun:

M= mass of sun =1.99x10^30 kg), m=mass of earth= 5.98x10^24kg) and R = 1.496 x 10^11 m, G=6.673 x 10^-11 N times m^2/ kg^2,

F = (6.673 x 10^-11 N times m^2/ kg^2,)(1.99x10^30 kg)(5.98x10^24kg)/(1.496 x 10^11 m)^2

= 3.54233552*10^22 N  is the force between earth and sun.

Between moon and sun:

M = sun's mass above, m = moon's mass = 7.36x10^22kg and R = Sun moon distance = Earth sun distance - Earth moon distance as both sun and moon and earth are on the same line= 1.496 x 10^11 m. - 3.84 x 10^8 m = 1.49214*10^11 meter.

F= (6.673 x 10^-11*1.99x10^30 *7.36x10^22)/(1.49214*10^11)^2

=4.38968*10^20 N is the force between sun and moon.

Between earth and moon:

F = (6.673 x 10^-11*5.98x10^24*7.36x10^22)/(3.84 x 10^8)^2

=1.991763064*10^20 N is gravitational force between earth and the moon.

The gravitational force exerted by sun on earth is 3.54233552*10^22 N  towards sun as calulated earlier and by same magnitude the earth exerts the force on sun , but towards earth.

Note:

(You did not provide the mass of the sun correctly. It should be 1.99*10^30 kg  and not 1.99*10^24 Kg  which is less than earth!).

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astrosonu | Student | (Level 1) Valedictorian

Posted July 27, 2012 at 11:17 AM (Answer #3)

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we should use the relation given by Newton.

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astrosonu | Student | (Level 1) Valedictorian

Posted July 27, 2012 at 11:31 AM (Answer #4)

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We should use it!!!

 

 

HA!!!!!!!!!!!!!!!!!!!!!!

 

ITS AN ORDER

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astrosonuthird | Student | (Level 1) Valedictorian

Posted August 4, 2012 at 9:14 AM (Answer #5)

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Yes!! Newtons law.

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