Someone is driving through a town at 12.0 m/s when suddenly a ball rolls out in front of them. You apply the brakes and begin decelerating at 3.5 m/s^2. a- How far do you travel before stopping? b- when you have traveled only half the distance in part (a), is the speed 6.0 m/s, greater than, or less than 6.0 m/s?

For part a) my answer was 20.6 m, even though I am not sure, and I am not sure how to find part b.

U need to use the kinematic formulas. One of them that will help u is
Vf=Vi+2a(d) Plug in the known and solve for the unknown.
For these problem you should practice using formula to avoid confusion but you also need to understand the concept of these problem.

Big d forgot to tell you to square the velocities. V^2=Vo^2 + 2ax