A platoon of soldiers marches on a road in steps accoridng to the sound of a marching band The band ils stoped and the soldiers are ordered to break the steps while crossign as bridge. Why?

Explanation

If the soldiers while crossing a suspended bridge march in steps, the frequency of marchind steps of soldiers may match with the natureal frequency of oscillations of the suspended bridge. In that situation, resonace will take place, then the amplitude of oscillations of th suspended bridge will increse enormously, which may cause the collapsing of the bridge. To avoid this situation, the soldiers are advised to go out of steps on suspended bridge.