# Time Equation Help Needed

1. Dec 16, 2009

### kriegera

Hi All - I am trying to find an equation that gives the time as a function of initial velocity, distance traveled, and specified acceleration. That is, t = some function of v(0), d, and a.

We ran a simulation problem for distances 25 and 50 meters and my times were - 4.099 and 6.141 respectively for initial velocity of 2.00 and inital acceleration of 2.00. i can't come up with any equations that fit my data. any input please?????

Thank you!
Ashley

2. Dec 17, 2009

### Staff: Mentor

Last edited by a moderator: Apr 24, 2017
3. Dec 17, 2009

### kriegera

So would it be:
t=SQRT(2s-v(o)/a

s=distance
v(o)=inital velocity

I've tried this but it doesn't give me the exact anser - is it ok to round up or down? Initally I found final velocity and then plugged it in but the challenge is to use one equation. Input?

Thank you!

4. Dec 17, 2009

### Staff: Mentor

The starting equation would be:
s = v0t + 1/2at2

To find t you'll need to solve the quadratic.

5. Dec 17, 2009

### kriegera

Thank you for this tip. I am not very "up" on my physics - this is my first introduction to it on a college level. What are the rules for solving for the quadratic? Does that involve derivitives? Thank you!

6. Dec 17, 2009

### Staff: Mentor

No need for calculus, just the 'quadratic formula'. (Google it!)

Note that I am assuming that your setup is one where the acceleration is constant. (You didn't actually state that.)

7. Dec 17, 2009