# Resonance

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#### pm1

##### Full Member

A pseudo discrete, thus passage info doesn't really matter.

A bldg in an earthquake may sway back and forth with gradually increasing amplitude until a collapse finally occurs. This is an example of:

A. Destructive interference
B. Doppler shift
C. Resonance
D. Young's modulus

I thought resonance occurred when there was oscillation with constant/maximum amplitude, not "gradually increasing". Doesn't it?

Thank you!

#### TheBoneDoctah

##### Full Member
Volunteer Staff
7+ Year Member
A pseudo discrete, thus passage info doesn't really matter.

A bldg in an earthquake may sway back and forth with gradually increasing amplitude until a collapse finally occurs. This is an example of:

A. Destructive interference
B. Doppler shift
C. Resonance
D. Young's modulus

I thought resonance occurred when there was oscillation with constant/maximum amplitude, not "gradually increasing". Doesn't it?

Thank you!

None
Of the answers are correct, so resonance is the "most correct"

##### MD
Moderator Emeritus
10+ Year Member
Resonance is the best answer. It's actually correct as well. Consider a swing set. If I begin with very little momentum, and pump in time with my swinging, my amplitude will gradually increase. The very fact that this occurs is because my pumping is done at a frequency that exhibits resonance with the oscillation of the swing. In this case, the energy is input from my body movement, but in the question, it's from the ground movement during the earthquake.

#### pm1

##### Full Member
Resonance is the best answer. It's actually correct as well. Consider a swing set. If I begin with very little momentum, and pump in time with my swinging, my amplitude will gradually increase. The very fact that this occurs is because my pumping is done at a frequency that exhibits resonance with the oscillation of the swing. In this case, the energy is input from my body movement, but in the question, it's from the ground movement during the earthquake.

hm okay, then how would you define resonance? it doesn't have to keep at a constant amplitude then, right?

thanks