Bifilar investigation compared with real lifesituationbridge

[hellokitty2016]

I did an experiment at school, about the bifilar pendulum, the experiment was with rulers and clampstands and strings to model a bridge. How would that be similar/different to the real life situation of an actual bridge.

e.g. effects of friction, or restoring force

 

[mfb]

What do you think?

Do you have a sketch of the experiment?