A train is traveling at 50msˉ¹ when the driver applies the brakes and..?

A train is traveling at 50msˉ¹ when the driver applies the brakes and gives the train a constant acceleration of -0.5msˉ² for 100s. Calculate the distance traveled by the train in 100s.

What do you need to know that for all you need to know is that if your wandering about on the track at the time you will surely DIE !!!
iF YOU CANT DO YOUR HOMEWORK ASK YOUR TEACHER FOR HELP !!!
bAZ

x = distance
v = velocity
a = acceleration
x(t) = 1/2 * a * t^2 + v * t

we know that
s=ut+.5at^2
=50*100+(.5)(-.5)(100)^2
=5000-2500
=2500m
=2.5km

u=50 m/s
a= -0.5 m/s^2
t=100 sec

s=ut-(0.5*a*t^2)
=(50*100)-(0.5*0.5*100^2)
=2500 m

Train travels 2.5 km