2026 · Q117
Which one among the following statements is correct?
general-sciencephysics-mechanics
- AThe total mechanical energy of a system is conserved if the forces, doing work on it, are conservative.
- BThe total mechanical energy of a system is conserved if the forces, doing work on it, are non-conservative.
- CThe total mechanical energy of a system remains constant.
- DEvery force encountered in mechanics does have an associated well-defined potential energy.
Explanation
Total mechanical energy (kinetic + potential) is conserved only when the net work is done by conservative forces, for which a potential energy can be defined. Non-conservative forces like friction dissipate mechanical energy, and not every force (e.g., friction) has an associated potential energy. Hence option A is correct.