Question

Discuss the symmetry between the laws of Charles Coulomb and Sir Isaac Newton regarding forces

Answer 1

Explanation :

(1) Charles Coulomb discovered the electrostatic force acting on two charged bodies.

According to him " the force of attraction or repulsion is directly proportional to the product of their charges and inversely proportional to the square of distance between them.''

$F=\dfrac{1}{4\pi \epsilon_0}\dfrac{q_1q_2}{r^2}$

where

$\dfrac{1}{4\pi \epsilon_0}$ is electrostatic constant.

While Sir Isaac Newton discovered the gravitational forces acting on two masses.

According to him " there exists a force in the universe which attracts every other object with a force which is equal to the product of their masses and inversely proportional to the square of the distance between them."

$F=G\dfrac{m_1m_2}{r^2}$

where,

G is universal gravitational constant.

(2) It is given that,

Charge, $q=1.25\times 10^{-19}\ N$

Force, $F=3\times 10^{-9}\ N$

We know that the relation between electric field and electric force is F = q E.

So, $E=\dfrac{F}{q}$

$E=\dfrac{3\times 10^{-9}\ N}{1.25\times 10^{-19}\ C}}$

$E=2.4\times 10^{10}\ N/C$

(3) It is given that,

Electric field, $E=2.8\times 10^4\ N/C$

Charge, $q=-4\times 10^{-6}\ C$

Since, F = q E

So, $F=-4\times 10^{-6}\ C\times 2.8\times 10^4\ N/C$

$F=-11.2\times 10^{-2}\ N$

Negative sign shows the force is attractive.

Hence, this is the required solution.

Answer 2

Base on the question, the answer and the explanation would be, Newton's law of gravitation has force proportional to the product of the masses of the two bodies and inversely proportional to the square of the distance between them. Coulomb's law is similar, with the charges replacing the masses; however, you can have repulsion (+)(+) or (-)(-) with electrostatics but only attraction with gravitation.