Question

"The first Tacoma Narrows Suspension Bridge collapsed in 1940. The poor design and

cheap construction was a prime factor. Explain what principle of physics describes the violent vibrations set in the bridge."

Answer 1

Collapse of bridge is a result of mechanical resonance.

For every structure there is a natural frequency at which maximum transfer of energy takes place.

For different cars or object plying on the bridge , may set off large amplitude of mechanical waves at a certain frequency. When this external frequency matches with the natural frequency of bridge maximum energy transfer takes place resulting in oscillations of bridge at maximum amplitude and thereby causing the structures to crack and ultimately destabilize resulting in the collapse of the bridge.