- #1

nathan scott

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## Homework Statement

In the 100 m dash a sprinter accelerates from rest to a top speed with an acceleration whose magnitude is 2.68 m/s

^{2}. After reaching top speed, he runs remainder of race with constant velocity. If total race is run in 12.0s, how far does he run during the acceleration phase?

## Homework Equations

d

_{1}= 1/2*2.68 m/s

^{2}*t

^{2}

d

_{2}= vt = 2.68 m/s

^{2}*t*12.0s - t

## The Attempt at a Solution

Not knowing if the above equations are correct I tried d

_{1}+d

_{2}=100m.

I multiplied everything, moved the 100m to the other side and tried the quadratic formula. I don't think I came out with the correct answer. I got approx. t= 3.5 or t= about 18. Any suggestions