Physics
posted by Jess on .
If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about ?
When I use the quadratic formula, I get 8.97

How can the time be negative?
0=10t4.9
0=t(104.9t)
t=0, t=10/4.9 sec are the solutions
In the quadratic equation:
(10+sqrt100)/9.8 = same answers.