### Central Force (Properties of central force) Lecture 1

## Central Forces: Properties and Applications

A central force is a type of force that acts along the line joining the centers of two interacting bodies and depends only on the distance between them. These forces play a crucial role in many physical systems, such as planetary motion, atomic structure, and satellite dynamics. Understanding the properties of central forces provides insight into various phenomena in classical mechanics and beyond.

### Properties of Central Forces

**Radial Nature:**- Central forces are always directed along the radial line joining the two interacting bodies.
- The force can be attractive (directed towards the center) or repulsive (directed away from the center).

**Dependence on Distance:**- The magnitude of a central force depends only on the distance r between the two bodies.

**Conservative Nature:**- Central forces are conservative, meaning the work done by the force around any closed path is zero.

### Applications of Central Forces

**Planetary Motion:**- The gravitational force between the Sun and the planets is a central force.
- Kepler’s laws of planetary motion are derived based on the properties of the gravitational central force.

**Satellite Dynamics:**- Satellites orbiting Earth experience a central gravitational force.
- Their orbits can be analyzed using the principles of central force motion.

**Atomic Structure:**- The electrostatic force between the nucleus and electrons in an atom is a central force.
- This force governs the structure and behavior of atoms and molecules.

**Projectile Motion with Air Resistance:**- In some cases, air resistance can be modeled as a central force, especially when it depends on the distance from a point.

Central forces are fundamental to many physical phenomena, from the motion of celestial bodies to the interactions within atoms. By understanding their properties, such as their dependence on distance and their conservative nature, we can analyze and predict the behavior of systems influenced by these forces. The conservation laws associated with central forces, including the conservation of angular momentum and energy, are powerful tools in solving complex problems in classical mechanics.

The Study Material includes both CSIR-NET/JRF, GATE Physics, and JEST Syllabus along with General Aptitude Section. Hard copy, as well as soft copy of the material, will be provided to the students.