# Homework Help: Velocity and Acceleration homework

1. Jan 17, 2007

### srh

1. The problem statement, all variables and given/known data
The acceleration of point A is defined by the relation a=-1.8sin(kt), where a and t are expressed in m/s^2 and seconds, respectively, and k=3 rad/s. Knowing that x=0 and v=0.6m/s when t=0, determine the velocity of point A when t=0.5s.

2. Relevant equations
a=dv/dt
a dt = dv
a=-1.8sin(3t)

3. The attempt at a solution
I began by using the equation a dt=dv. I substituted -1.8sin(3t) in for a. After integrating both sides I got v-v0=0.6cos(3t). I plugged in 0.6 m/s for v0. For t=0.5 I got v=.6424 m/s. The answer in the back of th book was 42.4mm/s. If I left v0 as zero, I would get that answer. But I thought I needed to include that. Am I missing something?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jan 17, 2007

### OlderDan

Think about the highlighted text. What function of the form v = f(t) is going to give you v0=0.6m/s?