Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 4.2 m/s2 for 3.2 seconds. It then continues at a constant speed for 13.2 seconds, before applying the brakes such that the car’s speed decreases uniformly coming to rest 220.0 meters from where it started. The yellow car accelerates uniformly for the entire distance, finally catching the blue car just as the blue car comes to a stop.
What is the acceleration of the blue car once the brakes are applied
The Attempt at a Solution
I found the distance traveled before the brakes were applied which was 198 m. I also found the speed at which it was constant which came out to be 13.44 m/s. These two values i have been confirmed is correct. I found the distance traveled after the brakes are applied which came out to be 22m (220.0-198).
So then i simply plugged the values into Vf^2=Vi^2+2ax → 0=(13.44)^2+2a(22)and solved for "a" but i got the wrong answer?