The Moon is most responsible for Earth’s tides. Which pulls more strongly on the Earth and its oceans?
A) Moon
B) Sun
C) Both about equally
Source: forum.understandingbasics
Solution. Posted on Sunday, May 10, 2015.
In order to answer this question we should use the Newton’s law of universal gravitation
F=G*M1*M2/r^2
Let’s calculate the gravitational force between the Earth and the Sun
F=6.67*10^-11*1.988*10^30*5.972*10^24/(1.5*10^11)^2 = 3.519*10^22 N
Now let’s calculate the gravitational force between the Earth and the Moon
F=6.67*10^-11*7.346*10^22*5.972*10^24/(3.7*10^8)^2 = 2.137*10^20 N
Let’s compare forces
3.519*10^22/2.137*10^20=165
Finally, the gravitational force from the Sun 165 times stronger than the gravitational force from the Moon.
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