Question

When a troop crosses a suspension bridge the soldiers are asked to break steps. Explain the reason.

Answer 1

When the troop crosses a suspension bridge the soldiers are asked to break steps because when the soldiers are in steps, all separate forces exerted by them are in same phase and hence the vibrations of a particular frequency are produced. If the natural frequency of the bridge is equal to the frequency produced, the bridge may start vibrating vigorously with a large amplitude due to resonance and may break.