A train is going at 28.9 m/s when the train engineer sees a car on the tracks and pulls the emergency brakes. If it takes the train 18.8 s to fully stop, how far did the train go before it stopped.

Answer 1

d = distance

d = v₁t + at²/2

a = (v₂ - v₁)/t < 0

Plug in

v₂ = 0 (full stop)

v₁ = 28.9 m/s

t = 18.8 s

and get a in m/s². Note that a is negative.

a = (0 - 28.9)/(18.8) m/s² = ?

Now plug this result for a, along with v₁ and t, into

d = v₁t + at²/2

and get the stopping distance in meters. You can finish from here.