A sprinter runs is running a 100m race. He accelerates at 2.8m/s^2 for 4.3 seconds and from there he finishes the race at a constant speed. What time does the sprinter finish the race?

Question

noelgreco · Answer

I think you mean, " He accelerates at 2.8m/s^2 for 4.3 seconds, and from there he finishes the race at a constant speed."

anonymous · Answer

Yes that is what I meant to say. I was thinking of when the sprinter reached their top speed when I wrote that Any idea how to solve it? I assume I am supposed to use the quadratic equation to solve for T right? But I am not sure how to set it up.

anonymous · Answer

Okay here's the idea:
In the first case, it is given; 
a = 2.8m/s^2
t = 4.3s
Let, s = x
Find final velocity using this data.

For the second case, 
final velocity of first case = initial velocity of second case.
final velocity of second case = 0 (finishes the race i.e. rest)
s = 100 - x.

anonymous · Answer

:)