How I find acceleration when know velocity and distance?

Question

The car stops 50 m after steady braking. What was the speed of the car before the start of braking if the deceleration during braking was 4.4 m/s

Answer 1

We can use the famous formula V_(final)² = V_(initial)² + 2ax

It stops so 0 = V_(initial)² + 2 ( -4.4 m/s²) x 50

V_(initial)² = 440 ==> V_(initial)² ∼= 21 m/s