a car attempts to stop and slides 25.5m while accelerating at -4m/s^2. The car's initial velocity was 20m/s. Find the time the slide took. Note that the final velocity is not known and that you need a quadratic solution.

Question

a car attempts to stop and slides 25.5m while accelerating at -4m/s^2. The car's initial velocity was 20m/s. Find the time the slide took. Note that the final velocity is not known and that you need a quadratic solution.

I know the quadratic formula, but I'm not sure how to plud in the values; could sombody please calrify. Thank you in advance. :)

Answer 1

Vf^2=Vi^2 +2a* disance

find Vfinal first. You have Vi, a, distance. Remember a is negative.

Now, knowing Vf.
Vf=Vi+ a*time
Now find time.
YOu do not need the quadratic formula.