Which one of the following is not a conservative force ?

A conservative force is defined as a force where the work done depends only on the initial and final positions, making it path-independent [1]. Examples of conservative forces include gravitational force, electrostatic (electric) force, and spring (elastic) force. These forces allow for the storage of potential energy and conserve mechanical energy in a closed system [1]. In contrast, non-conservative forces are path-dependent and dissipative, meaning they convert mechanical energy into other forms like heat or sound [1]. Frictional force is a classic example of a non-central, non-conservative force because the work done by friction depends on the specific path taken and results in energy dissipation [1]. Therefore, among the given options, frictional force is the only one that is not a conservative force.

Sources

1. [1] https://www.aakash.ac.in/important-concepts/physics/conservative-and-non-conservative-forces