# Thread: Fsc 2nd Year chapter No :1 | ELECTROSTATICS

1. ## Fsc 2nd Year chapter No :1 | ELECTROSTATICS

Fsc 2nd Year chapter No :1 | ELECTROSTATICS

Topic No :11

COMPARISION BETWEEN ELECTRIC AND GRAVITATIONAL FORCES

wo huge differences: 1). The electrostatic force per unit Q2 exceeds the gravitational force per unit M2 by a factor of almost 1040.

2). Positive and negative Q exist, leading to attractive and/or repulsive electrostatic force; but negative mass does not exist, and gravitational force is always attractive.

1. The problem statement, all variables and given/known data

Which two of the three types of fields in the title of this are thread are the most similar? Provide supporting evidence?

2. Relevant equations

Gravitational:
-Source: point mass
-Field intensity proportional to: M/r^2
-Range: long range
-Strength: weak
-Direction of field lines: toward center of mass

Electric Fields:
-Source: point charge
-Field intensity proportional to: Q/r^2
-Range: short range
-Strength: strong
-Direction of field lines: toward center of charge

The strength of each force is determined in part by a (different) "fundamental constant". And each force is inversely proportional to the square of the distance separating the bodies involved.

The difference is that gravity is always attractive (as far as we can tell), where as the electric force may be either attractive or repulsive, depending upon the charges involved.

Another similarity is that the strength of the forces are proportionate to the respective characteristics of the bodies involved. In the case of gravity, the masses of the bodies determines the force. With electric, the charge of the bodies affects the force.

The equations for the forces are highly similar:
Gravity: f = -G(m1*m2)/(r^2)
Electric: f = k(q1*q2)/(r^2)

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