1. Jan 24, 2005

### VeeVee151

A truck covers 40.0 m in 7.65 s while smoothly slowing down to final speed 3.40 m/s. whats the original speed and what is its acceleration?? The initail position is 0, the final position is 40. THe initial velocity we don't know, the final velocity is 3.40 m/s. The time it takes is 7.65 and the acceleration we don't know. Do I have that right? and when I set it up in the formulas there are two unknowns and I work it out and it never comes out to be the right answer.

Last edited: Jan 24, 2005
2. Jan 24, 2005

### Curious3141

Are you familiar with :

$$s = vt - \frac{1}{2}at^2$$

and $$v = u + at$$ ?

use the 1st to solve for a (you're given the rest), then use that value of a to find u with the second equation.