(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

mass of star = 2.53 x 1030 kilograms

mass of planet = 5.25 x 1024 kilograms

mass of moon = 8.09 x 1022 kilograms

average distance from star to planet = 1.14 x 1011 meters

average distance from planet to moon = 4.59 x 108 meters

Use the data above to determine the net force exerted on the moon by the planet and the star during:

a. a solar eclipse.

WebAssign will check your answer for the correct number of significant figures. wrong check mark N

b. a lunar eclipse.

WebAssign will check your answer for the correct number of significant figures. wrong check mark N

2. Relevant equations

Fg=G x M1 x M2/Dsquared

Note that the lineup for a solar eclipse is Sun-Moon-Earth

A lunar eclipse lineup is Sun-Earth-Moon

This I am sure of.

3. The attempt at a solution

My attempt was to find the netforce of gravity on the moon.

Here is my work which produced a wrong answer.

a) Fgrav,net=Gm(moon)M(sun)/Dsquared(the distance between the star and the planet- the distance between the planet and the moon) - GM(moon)M(earth)/dsquared

Perhaps I added the distances wrong- but I know when the moon is in the middle I will have opposite signs for the forces from each planet and the lunar eclipse should produce. I got 9.18E20 rounded for my answer to part a. Any ideas? Am i using the distance wrong? Any similar answers? Any other forces to be accounted for in the net sum? Thanks.

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# Homework Help: Universal Gravitation and mass

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