What is the oscillatory system in this A Level physics bridge example?

So I was answering a question which asked you to describe an example of resonance. You had to say what the oscillatory system is, what provides the driving force, and what the consequences of the resonance are.

I picked footsteps at the same frequency as the natural frequency of a bridge causing it to shake, which the mark scheme said was a valid answer. However it didn't say what the oscillatory system would be? I'm unsure if the bridge by itself is the whole oscillatory system, or if the bridge *and* the footsteps/the people walking across are together the system? Can someone please confirm? :smile:

Reply 1

lordaxil

Strictly speaking the people are part of the oscillatory system as well, as they provide a bit of extra mass, but since the mass of bridge is likely to be much larger than the people on it then I think it's OK to regard the bridge by itself as the oscillatory system.