# Homework Help: Simple harmonic motion acceleration

1. Nov 3, 2014

### pyman999

1. The problem statement, all variables and given/known data

2. Relevant equations
acceleration = -(2*pi*f)^2 * x, where f is the frequency and x is the displacement from equilibrium.

3. The attempt at a solution
I thought the acceleration would be greatest when the displacement from equilibrium is greatest, so at point P, but the answer is at point R and I'm not sure why.

2. Nov 3, 2014

### BvU

Re relevant equation: since there is damping, the expression for the acceleration is a little different: generally the damping force is taken to be proportional to the speed, so there is a term in the force $-\beta v$ and we write $$m a + \beta v + k x = 0$$ so that $$a = -{\beta \over m} v - {k\over m} x$$

Re where magnitude of a is maximum: I agree with you. Both at P and R |v| = 0 and |x| is bigger at P.

3. Nov 3, 2014

### pyman999

I'm fairly sure the answers I have been given for this question are wrong then, as I'm also getting weird results for later parts, thanks.