# 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