Question

In the absence of non-conservative force like friction. Which of the following is true about mechanical energy during such a process?
A. The total mechanical energy (kinetic + potential) changes, but the individual energies (kinetic and potential) may vary.
B. The total mechanical energy remain constant ,But the individual energies (kinetic + potential) can vary
C. Mechanical energy is lost to internal energy
D. The system’s kinetic energy decreases and potential energy increases continuously.

Answer 1

B.

If no non‑conservative forces (like friction) act, mechanical energy is conserved: K + U = constant. Kinetic and potential energies can exchange (e.g. pendulum, mass on a spring), but their sum remains the same.