Why do soldiers march disorderly while crossing a bridge?

A.

To prevent resonance on the bridge

B.

To set the bridge into resonance

C.

To make the b ridge collapse

D.

To spread their weight evenly on the bridge

Correct answer is A

Soldiers march disorderly while crossing a bridge to prevent resonance because when soldiers march in orderly manner across a bridge, they generate a rhythmic oscillation of wave on the bridge and at a certain point, would start oscillation to the same rhythm as that of the marching steps. This oscillation would reach a maximum peak when the bridge can no longer sustain its own strength and hence collapses. So for this reasons, soldier are ordered to march disorderly while crossing a bridge.