Question

Two unequal masses are ties together with a cord with a compressed spring in between.
Which of the following energies is conserved for the system?
A. (a) Kinetic energy
B. (b) Potential energy
C. (c) Mechanical energy
D. (d) None of these

Answer 1

Correct Answer - C
Initial KE of the blocks is zero (as both are at rest) and after some time KE of the blocks is not zero (as both are in motion). So KE is not constant but changes. Potential energy of spring converts into KE of blocks such that mechanical energy remains conserved.