. If a train going 60 m/s hits the brakes, and it takes the train 25 seconds to stop, what is the train’s acceleration

First things first: Name the variables

v= final velocity( velocity after the train stops)

u= intial velocity(velocity when the train was moving at constant speed, before brakes are applied)

a= acceleration( in this case, it is deceleration)

t= time ( time taken to fully stop)

Second Step: What equation should we use?

The 3 Big Motion in One Dimension Formulas are:

v= u+at

v^2= u^2 + 2as

s= ut+ (1/2) at^2

For this question, we will be using the first one.

Third Step: Solve

v= 0 (the final velocity is 0, because the train stopped)

u= 60 (the train was going at 60 mps)

t= 85 seconds( 1 min and 25 sec)

0= 60+ 85a

Solving for a gives you,

a= -12/17 m/s ^2

I hope this helped!