Final Answer:
Non-conservative forces, unlike conservative ones, don't conserve total mechanical energy. Thus, the correct option is b) It dissipates mechanical energy.
Step-by-step explanation:
A non-conservative force is a force that does work on an object but does not store that work as potential energy. In the case of non-conservative forces, the total mechanical energy of a system is not conserved. The work done by a force can either add or subtract from the mechanical energy of the system, leading to a dissipation of energy.
Consider a particle of mass _m_ moving in a conservative force field, such as gravity. The work done by the conservative force in moving the particle from position _A_ to position _B_ is given by the change in potential energy, which is path-independent. Mathematically, this is expressed as W_AB = ΔU = U_B - U_A, where U is the potential energy.
However, for a non-conservative force, the work done depends on the path taken. If the particle moves from _A_ to _B_ under the influence of a non-conservative force, the work done, W_AB, is not equal to the change in potential energy. Instead, there may be losses due to friction, air resistance, or other dissipative effects.
In summary, the physical meaning of a non-conservative force lies in its ability to dissipate mechanical energy. Unlike conservative forces, which contribute to potential energy changes, non-conservative forces lead to the dissipation of energy as they perform work on a system. This distinction is crucial in understanding the conservation of energy in various physical systems.
b) It dissipates mechanical energy.