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Gravitational & Electric Forces: Similarities & Differences

Last updated on April 20th, 2023 at 05:07 am

Gravitational & Electric Forces: Similarities & Differences – This topic is a comparative study between Electric force and Gravitational force. The electric force is related to electric charges and Gravitational force is applied between any two masses. The electric force is also called electrostatic force. A force of either attraction or repulsion that a body exerts on another body due to its charge is called electrostatic force. A force of attraction that a body exerts on another body due to its mass is called gravitational force.

Similarities between Electric Force and Gravitational force

Coulomb’s law for the force between two charges looks pretty similar to Newton’s law of gravitation for the force between two masses.

Both laws are inverse-square laws, meaning the force diminishes with the square of the distance.

The product of the two charges in Coulomb’s law resembles the product of the masses in Newton’s law.

Differences between the Electric Force and Gravitational force

There are a couple of important differences between Electric force (electrostatic force) and gravitational force.

1 ) One is that the electric force can be attractive or repulsive, depending on the signs of the charges, but the Gravitational force is always attractive.

2 ) Another important difference is the strength of the Gravitational force and electricity. Electric Force is much stronger than Gravitational force. The gravitational force is comparatively a weaker force.

3 )Electrostatic force is exists due to charge on the body. Gravitational force is only due to mass of the body.

4 ) A force of either attraction or repulsion that a body exerts on another body due to its charge is called electrostatic force or electric force. A force of attraction that a body exerts on another body due to its mass is called gravitational force.

5 ) Electrostatic force depends on the medium in which the bodies are placed. The gravitational force is not affected by the medium in which the two bodies are placed.

6 ) In case of electrostatic force, the constant of proportionality is ‘k’ whose value depends on the medium. The gravitational constant (G) (which is the constant of proportionality) has a value that is constant at any point in this universe.

show that the strength of the electric force is greater than the strength of the gravitational force

We can compare the two forces by considering a hydrogen atom, where a proton and electron attract each other electrically and gravitationally. Here we will use the average distance between the proton and the electron = r = 5.3 × 10-11 m.

Now, using Newton’s Law of Gravitation, we get 3.6 × 10-47 N for gravity. As we use Coulomb’s law, we received 8.2 × 10-8 N for the electric force between the proton and electron.

That’s a huge difference. The electric force is a clear winner with a magnitude almost 1039 times the magnitude of the gravitational force.

This clearly explains why electric forces dominate over gravity even when we have a fairly slight excess of charge, such as when we’ve run a comb through our hair.

The big difference in the strength of the two forces also tells us that whenever gravitational force is the dominant force, the bodies involved are extremely neutral electrically. For example, Earth’s orbit around the sun is accounted for by Newton’s law of gravitation. That tells us that the net charge on Earth is pretty small.

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