Homework Help: Classical Mechanics: Simple harmonic oscillator problem

1. Jan 21, 2012

JordanGo

1. The problem statement, all variables and given/known data
A simple harmonic oscillator with mass m = 1/2 and k = 2 is initially at the point
x = √3 when it is projected towards the origin with speed 2.
Find the equation of motion describing x(t).

2. Relevant equations

x=Asin(ωt+θ)

3. The attempt at a solution

At t=0, x=√3

√3=Asin(θ)

There is two unknowns and only one equation...I'm stuck

2. Jan 22, 2012

gomboc

You just need to use a little ingenuity to solve for A.

You know that the mass is projected towards the eq point from x=sqrt(3) with velocity 2. Since you know the spring constant and the mass, you can find the mass's total energy, and thus it's position (A) at maximum extension using conservation of energy.

3. Jan 22, 2012

technician

Do you recognise that ω = √k/m ?

4. Jan 22, 2012

JordanGo

K, well I did a lot of work on white board and my conclusion is:
x(t)=2sin(4t-pi/3)
Does this make sense? Do you need to see all my work?