All of the following forces are central force, EXCEPT
A)Coulomb force
B) Frictional force
C)Gravitational force
D)Electrostatic force
To determine which force is not a central force among the given options, we need to understand what a central force is.
A central force is a force that is directed towards or away from a fixed point in space, known as the center. Mathematically, a central force always points radially, meaning it either pulls objects towards the center or pushes them away.
Now, let's analyze each of the given options to identify whether they are central forces or not:
A) Coulomb force: The Coulomb force is the electrostatic force between charged particles. It follows Coulomb's law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Since this force follows a radial direction, it is a central force.
B) Frictional force: Frictional force opposes the relative motion or tendency of motion between two surfaces in contact. Friction acts parallel to the surfaces and opposes motion. It does not have a radially directed force, so it is not a central force.
C) Gravitational force: The gravitational force is the force of attraction between two objects with mass. It follows the law of universal gravitation, which states that the force is directly proportional to the product of the masses and inversely proportional to the square of the distance between them. Like the Coulomb force, it follows a radial direction and is a central force.
D) Electrostatic force: The electrostatic force is the force between charged objects that are not in motion. It is similar to the Coulomb force but specifically refers to objects at rest. Like the Coulomb force, it follows a radial direction and is a central force.
By process of elimination, we can conclude that the force that is not a central force among the given options is:
B) Frictional force