Forced oscillation (mass & spring)

1. Nov 2, 2008

kash25

1. The problem statement, all variables and given/known data
A 2 kg object attached to a spring moves without friction and is driven by an external force given by F = (3.00N)sin(2$$\pi$$t). The force constant of the spring is 20.0N/m.
Find the amplitude of the motion.

2. Relevant equations
I am not sure but I am trying to use:
A = (F0/m)/$$\sqrt{}(w^2-w0^2)^2$$

3. The attempt at a solution
Applying this equation using w equals 2pi and w0 is k/m (10) gives an amplitude of 0.00173. The solution in the book says 5.09cm.
Am I approaching this question correctly?

2. Nov 2, 2008

alphysicist

Hi kash25,
w0 is not equal to k/m. If you correct this you should get the right answer.

3. Nov 2, 2008

Gear300

Not exactly sure...but that equation you have might be for forced oscillations working against friction; in this case there is no friction.

4. Nov 2, 2008

alphysicist

No, it's the right equation. If it was a damped spring there would be another term under the radical. Using that equation (with the corrected value for w0) gives the answer given in the post.

5. Nov 2, 2008

Quachama

remember that w0 = sqrt (k/m).

That will give you the right answer :)

6. Nov 2, 2008