Question

If a train going 60m/s hits the brakes and it takes the train 1 minute 25 seconds to stop what is the acceleration?

Answer 1

Given:

The initial speed of the train is,

$u=60\text{ m/s}$

The time to stop is,

$\begin{gathered} t=1\text{ m 25 s} \\ =(60+25)\text{ s} \\ =85\text{ s} \end{gathered}$

The final speed is,

$v=0$

To find:

The acceleration

Explanation:

Using the formula of speed,

$v=u+at$

Here, a is the acceleration.

Substituting the value we get,

$\begin{gathered} 0=60+a\times85 \\ a=-\frac{60}{85} \\ a=-0.71\text{ m/s}^2 \end{gathered}$

Hence, the acceleration is,

$a=-0.71\text{ m/s}^2$