Question
Tue February 07, 2012 By: Michelle

What are the similarities and dissimilarities between gravitational force and electrostatic force?

Expert Reply
Tue February 07, 2012
Gravitational force is the force generated between two masses, such as the Earth and the Moon, an apple and the Earth, or anything else possessing mass in the universe. As a matter of fact, Mars is exerting a gravitational force on you - it extends forever. The formula for gravitational force is: Fgrav. = (Gm1m2)/(d2) where G is the gravitational constant 6.67 x 10-11 m1 is one mass in kilograms, m2 is the other mass d is the separation distance in meters between the two masses. Electrostatic forces: Electrostatic force exists between two charged objects. Unlike gravitational force, electrostatic force can be either a force of ATTRACTION or one of REPULSION, depending on the nature of the two charges; like charges repel, opposites attract. But this force also extends forever and its formula is surprisingly similar to the gravity formula: Felectrostatic = (Cq1q2)/(d2) where C is Coulomb's constant 8.99 x 10-9 q1 is one charged object in coulombs of charge, q2 is the other. d is the separation distance in meters. But question is , whether the two objects in question will attract or repel. For instance, a proton has a charge of +1.60 x 10-19 C. An electron has a charge of -1.60 x 10-19 C. They are opposite, so they will attract. The electrostatic force per unit Q2 exceeds the gravitational force per unit M2 by a factor of almost 1040.
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