Sudut Fizik : Maklumat 2010

Bridges and other structures have a natural frequency that depends on their size and shape. If vibrations match this frequency, the bridge can vibrate wildly and even collapse.

If soldiers march in step across a bridge at the bridge's natural frequency, the magnified oscillations can break the bridge apart. This happened a couple of times in the 19th century, so now, soldiers break step when marching across a bridge.

The Tacoma Narrows bridge collapse in 1940, shortly after it was completed, is the most dramatic example of a resonating bridge collapsing. The bridge vibrated so much it was often called Galloping Gertie. Winds through the narrows vibrated the bridge at its natural frequency. Resonance amplified the vibrations until the bridge collapsed. Engineers now try to eliminate resonances when designing bridges.

Resonant phenomena occur often in nature. The effects can be either good, as in music, or bad, as in collapsing bridges.