Posted by
Hannah on
.
Determine the final speed assuming that the time elapsed since t=0 is 2.4s.
Initial velocity is +12m/s
acceleration is +3.4m/s^2
I tryed doing 12/2.4 and then 12/3.4 but both of these were incorrect? I am not sure what to do.
Thank you.

Physics(Please help) 
drwls,
Here is what you know:
V(t) = Vo + (a/2)t^2
Vo = 12 m/s
a = 3.4 m/s^2
t = 2.4 s
V(t=2.4) = 12 + 1.7 * (2.4)^2
= 21.792 m/s

Physics(Please help) 
Hannah,
When I put 21.792 m/s as my answer my online homework said it was incorrect. Why??