# Mass spring system.

1. Oct 24, 2016

### Dusty912

1. The problem statement, all variables and given/known data
A simple harmonic oscillator consists of a block of mass 2.00 kg attached to a spring of spring constant 100 N/m.When t =1.00 s, the position and velocity of the block are x =0.129 m and v =3.415 m/s. (a) What is the amplitude of the oscillations? What were the (b) position and (c) velocity of the block at t 0 s?

2. Relevant equations
x(t)=X*cos(ωt+Φ)
v(t)=-ω*X*sin(ωt+Φ)
ω=sqrt(k/M)

3. The attempt at a solution
so finding the angular velocity was easy. Just plugging in the values for k and m yielded 7.07rad/s
i lost on where to go next. I think my understanding of the phase and Φ is a little weak. I was to just use the equation for displace meant and velocity, make Φ zero and plug in the other values, but I am prety sure that is wrong.

2. Oct 24, 2016

### Staff: Mentor

For (a) you might want to consider an energy approach.

3. Oct 25, 2016

### J Hann

Note what happens if you divide v by x (using the formulas that you provided).
The amplitude cancels and you are left with only one unknown (phi).
Then the rest of the problem should be straightforward.