# Need help with amplitude problem

1. Dec 9, 2004

### cutegirl1980

box of mass 2kg on spring with k=13 N/m, they are on a wheel. The road has an amplitude δ = 2 cm as shown above. What speed is necessary for the
mass to have a maximum amplitude x = 2δ . the picture looks something like this
__
|__| m=2kg
\
/ k=13 N/m
\
/--\__________________
\--/ 16.0 cm

^ the thing the bottom of the spring is connected to looks like a wheel. the distance is 16 cm. can anyone help me, very confusing question.

2. Dec 9, 2004

### Staff: Mentor

This is a simple harmonic motion problem with a forcing function.

Write the equation for SHO without damping and with a forcing function.

See http://hyperphysics.phy-astr.gsu.edu/hbase/shm2.html for some basic equations.

You know that the amplitude of the mass on the spring has to be twice the amplitude of the forcing function, and you have to find the frequency of the forcing function that will give you that amplitude.

Remember how to find the frequency of a mass (m) on a spring with constant (k).