SfC Home > Physics > Gravitation > Show by Ron Kurtus You can find the gravitational force between two objects by applying the Universal Gravitation Equation, provided you know the mass of each object and their separation. With this equation, you can make calculations to determine such things as the force between the Earth and the Moon, as well as between two large masses. Questions you may have include:
This lesson will answer those questions. Useful tool: Units Conversion The Universal Gravitation Equation is:
where
Force attracting Earth and MoonTo calculate the gravitational force pulling the Earth and Moon together, you need to know their separation and the mass of each object. DistanceThe Earth and Moon are approximately an average of 3.844*105 kilometers apart, center to center.
Since the units of G are in N-m2/kg2, you need to convert the units of R to meters.
Mass of each objectLet M be the mass of the Earth and m the mass of the Moon.
Force of attractionThus, the force of attraction between the Earth and Moon is:
Attraction between Earth and Moon Result of forceThis considerable force is what holds the Moon in orbit around the Earth and prevents it from flying off into space. Inward force of gravitation equals the outward centrifugal force from the motion of the Moon.
Also, the gravitational force from the Moon pulls the oceans toward it, causing the rising and falling tides, according to the Moon's position.
Force attracting large objectsIn the same manner, you can calculate the gravitational force attracting two large objects. Suppose you had an object with mass of 100 kg, another with a mass of 200 kg, and the separation of their centers was 2 meters.
Simplify:
That is a very small force attracting the objects together. However, even a smaller force was measured in the Cavendish Experiment to Measure Gravitational Constant. SummaryYou can apply the Universal Gravitation Equation to show the force of attraction between two objects, such as the force between the Earth and the Moon, as well as between two large masses. Think clearly and logically Resources and referencesRon Kurtus' Credentials WebsitesConverting units of mass to equivalent forces on Earth - Wikipedia Weight - Mass - Kilogram - Mass and Weight: the Gravity Force - Engineering Toolbox Gravitation Resources Books(Notice: The School for Champions may earn commissions from book purchases) Top-rated books on Gravity Top-rated books on Gravitation Questions and commentsDo you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible. Share this pageClick on a button to bookmark or share this page through Twitter, Facebook, email, or other services: Students and researchersThe Web address of this page is: Please include it as a link on your website or as a reference in your report, document, or thesis. Copyright © Restrictions Where are you now?School for Champions
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