Question

If a train going 60 m/s hits the breaks, and it takes the train 85 seconds to stop, what is the train´s acceleration

Answer 1

Acceleration is change in velocity over time --> $a = \frac{Δv}{t}$

Δv or change in velocity equals the Final velocity minus the initial velocity

Our initial velocity here is 60m/s while our final velocity is 0 m/s

The time interval is 85 seconds so...

$a = \frac{0-60}{85}$

$a = \frac{-60}{85}$

$a = -0.706$

The negative is there to indicate that the train in slowing down or decelerating