Re: [Phys-l] Why soldiers break step on small bridges, and not so small.

[Bernard Cleyet <bernardcleyet@redshift.com>]

Ahhh.  It may be one must be a member of the physics fora.

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I'm doing this problem from Mastering Physics, and I'm really stuck on this problem

Assume that, when we walk, in addition to a fluctuating vertical force, we exert a periodic lateral force of amplitude 25 N at a frequency of about 1 Hz. Given that the mass of the bridge is about 2000 kg per linear meter, how many people were walking along the 144 m-long central span of the bridge at one time, when an oscillation amplitude of 75 mm was observed in that section of the bridge? Take the damping constant to be such that the amplitude of the undriven oscillations would decay to 1/e of its original value in a time t=6T, where T is the period of the undriven, undamped system.


Can someone please help me with this?

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bc




On 2011, Jul 30, , at 08:34, Anthony Lapinski wrote:

> Did not work. What's the link? Bridge video?
>
> Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu> writes:
> > while searching I found this Ceylon:
> >
> > http://www.physicsforums.com/showthread.php?t=100679
> >
> >
> > If the above doesn't work for "you", I'll copy and send.
> >
> > bc