# A train is moving at a constant velocity of "5 m/s". After it exists a tunnel, it starts to accelerate with an acceleration of "9 m/s"^2 for "5 s". What is the velocity of the train after "5 s" ?

Jun 14, 2017

$50$ $\text{m/s}$

#### Explanation:

We're asked to find the velocity of the train after $5$ $\text{s}$ with a given initial velocity and acceleration.

To solve this, we can use the equation

${v}_{x} = {v}_{0 x} + {a}_{x} t$

where

• ${v}_{x}$ is the velocity at time $t$ (what we're trying to find)

• ${v}_{0 x}$ is the initial velocity ($5$ $\text{m/s}$)

• ${a}_{x}$ is the acceleration ($9$ ${\text{m/s}}^{2}$)

• $t$ is the time ($5$ $\text{s}$)

Plugging in known values, we have

v_x = 5"m/s" + (9"m/s"^2)(5"s") = color(red)(50 color(red)("m/s"

The final velocity (the velocity at time $t = 5$ $\text{s}$) is thus color(red)(50 meters per second.