Simple Harmonic Motion on a moving platform

chrisy2012

I had my physics midterm today and I totally blanked out. I want to know how to solve it for next time.

So In the picture, there are two springs connected to the mass on a platform.
a) if the platform is at rest, find the angular frequency

the expression for angular frequency is :ω=√(k/m), so I just added the two k's and plugged it into k and got :ω=√((k1+k2)/m). Is this correct?

b)The platform then started to move in SHM with the equation d(t)=D*cos10∏t. We had to find the amplitude of mass M. This is where I tripped up and don't know how to solve it. Any ideas?

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tiny-tim

hi chrisy2012!
maybe!

how would you prove it?

find the positions of the two endpoints as functions of t, and that will help you find the distances to multiply by the spring constants