Final answer:
Non-conservative forces are those forces that dissipate mechanical energy from a system due to their path-dependent work, such as applied forces and friction.
Step-by-step explanation:
Examples of non-conservative forces include applied forces and friction. These forces result in the loss or dissipation of mechanical energy from a system because of their path-dependent work. Unlike conservative forces, such as gravitational force, which have associated potential energies and enable system energy recovery, non-conservative forces like friction generate thermal energy that cannot be completely reconverted into mechanical energy. Tension and elastic (spring) force are contact forces, but they are not necessarily non-conservative, as they often can store and return energy without dissipation. Therefore, the correct option is Option 2: Applied forces and friction.