91影视

Any mechanical objects or charged particles tend to vibrate at a particular frequency. This frequency is called the natural frequency of the object. When light or sound waves oscillating at a particular frequency strikes the object, it interacts with the object鈥檚 vibration. If that frequency happens to match the natural frequency of the object, then the phenomenon of mechanical resonance takes place.

During resonance, the mechanical object responds at a greater frequency. Vibration at higher amplitudes may cause violent catastrophic failures and destructions in mechanical structures.

Bridges have their own natural frequency of vibration. If soldiers march in unison across the bridge, they apply a force in the bridge which generates a wave with a particular frequency. If that frequency matches the bridge鈥檚 natural frequency, it will amplify the bridge鈥檚 vibrating amplitude.

If mechanical resonance is strong enough the bridge may vibrate until it collapses from the movement. That is why Soldiers are ordered to 鈥渞oute step鈥� across a bridge to avoid creating mechanical resonance.