# Amplitude of oscillation?

1. Nov 18, 2008

### kristibella

1. The problem statement, all variables and given/known data
A 200 g ball attached to a spring with spring constant
2.50 N/m oscillates horizontally on a frictionless table. Its velocity is 18.0 cm/s when x = -5.00 cm.
A. What is the amplitude of oscillation?

B. What is the speed of the ball when x = 3.00 cm?

2. Relevant equations
A. $$\omega$$ = sqrt k/m = sqrt 2.50/.200
v(t) = A*$$\omega$$*sin($$\omega$$t)
t = 0
v(t) = A$$\omega$$

B. Vx2 = $$\omega$$2(A2 - x2)

3. The attempt at a solution
I've tried several times to get a solution and I have never gotten the same answer twice...
A. $$\omega$$ = 3.54
A = 5.09 cm

B. When x = 3.00 cm, V = 14. 56 cm.

Neither of these answers are correct and I'm not sure what I am doing wrong. I am doing everything as explained to me in class. I'm so confused...

Last edited: Nov 19, 2008
2. Nov 18, 2008

### Redbelly98

Staff Emeritus
Have you been taught about conservation of energy, and the potential energy of a spring?

Also, is there supposed to be a question in part A? I only see a question in B.