How to solve this ratio/proportionality question?

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SUMMARY

The gravitational pull of the Moon on the Earth's oceans is approximately 3 millionths of the gravitational pull of the Earth on its oceans. This conclusion is derived from the gravitational field strength of the Moon, calculated as 3.40 x 10^-5 N/kg, compared to the Earth's gravitational pull of 9.8 N/kg. The ratio is determined by dividing the Moon's gravitational pull by that of the Earth, confirming the relationship as 3/1,000,000. Understanding this ratio is essential for solving physics problems related to gravitational forces and tidal effects.

PREREQUISITES
  • Understanding of gravitational force and field strength
  • Familiarity with the formula g = GM/r²
  • Basic knowledge of ratios and proportionality
  • Concept of tidal forces caused by celestial bodies
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  • Study gravitational force calculations using the formula g = GM/r²
  • Learn about tidal forces and their effects on Earth
  • Explore ratio and proportion problems in physics
  • Investigate the gravitational interactions between celestial bodies
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Students studying physics, educators teaching gravitational concepts, and anyone interested in understanding the mechanics of tides and celestial interactions.

Tangeton
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The Moon's gravitational pull on the Earth causes the ocean tides. Show that the gravitational pull of the Moon on the Earth's oceans is approximately 3 millionths of the gravitational pull of the Earth on its oceans. Assume that the distance from the Earth to the Moon is 380,000 km.
Other given/worked out previously: mass of moon = 7.35 x10^22kg, surface gravitational field strength of the moon: 1.62Nkg^-1, radius of the moon = 1740km (3sf)

g at the Earth's surface is 9.8.
g at moon's surface I worked out using the formula g = GM/r^2,g * mass of moon/ distance from moon to Earth sqred = 3.40x10^-5 (3sf)

My big problem is the ratios. How do I show that its 3/1000000 of the grav. pull of the Earth? I know that grav pull of the Earth on oceans will be 9.8 and the moon on the ocean will be 3.40x10^-5, but I just simply do not know how to do physics ratio questions whatsoever. I am terrible at them... How do I approach ratio/ proportionality question such as this one? What is the process?
 
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Tangeton said:
The Moon's gravitational pull on the Earth causes the ocean tides. Show that the gravitational pull of the Moon on the Earth's oceans is approximately 3 millionths of the gravitational pull of the Earth on its oceans. Assume that the distance from the Earth to the Moon is 380,000 km.
Other given/worked out previously: mass of moon = 7.35 x10^22kg, surface gravitational field strength of the moon: 1.62Nkg^-1, radius of the moon = 1740km (3sf)

g at the Earth's surface is 9.8.
g at moon's surface I worked out using the formula g = GM/r^2,g * mass of moon/ distance from moon to Earth sqred = 3.40x10^-5 (3sf)

My big problem is the ratios. How do I show that its 3/1000000 of the grav. pull of the Earth? I know that grav pull of the Earth on oceans will be 9.8 and the moon on the ocean will be 3.40x10^-5, but I just simply do not know how to do physics ratio questions whatsoever. I am terrible at them... How do I approach ratio/ proportionality question such as this one? What is the process?
You're nearly there, what do you get if you divide the moon's pull on the ocean, by the Earth's?
 
Vagn said:
You're nearly there, what do you get if you divide the moon's pull on the ocean, by the Earth's?
Okay that was too easy. Thanks.
 

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