# Variable acceleration with one premise

1. Sep 13, 2010

### pf_001

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

A particle's acceleration is given by the equation a(t) = 2t + 1 m/seg^2. If its velocity at t = 2 equals 5 m/seg, how much does its displacement change from t = 2 to t = 4?

2. Relevant equations

3. The attempt at a solution

I thought I could integrate the acceleration equation to get the velocity equation, but when I solve this equation for t = 2, I don't get 5 m/seg as the problem states. Here's the equation I came up with:

v(t) = t^2 + t

Should I add a -1 to the end so the equation satisfies the premise?

2. Sep 13, 2010

### zorro

What is seg?

3. Sep 13, 2010

### pf_001

I'm sorry, second.