# A helicopter’s speed increases from 25 m/s to 60 m/s in 5 seconds. What is the acceleration of this helicopter?

Apr 17, 2018

The answer is ${\text{7 m/s}}^{2}$.

#### Explanation:

$\text{Acceleration}$ = ("final speed " - " initial speed")/"time"

So

a = ("60 m/s " - " 25 m/s") / "5 s"

$a = \text{35 m/s" / "5 s}$

$a = {\text{7 m/s}}^{2}$

Apr 18, 2018

$7 \setminus {\text{m/s}}^{2}$

#### Explanation:

We use the basic kinematics equation,

$v = u + a t$

• $u$ is the initial velocity of the object

• $a$ is the acceleration of the object

• $t$ is the time taken

Rearranging for $a$, we get:

$a = \frac{v - u}{t}$

• $v$ is the final velocity of the object

And so,

$a = \left(60 \setminus \text{m/s"-25 \ "m/s")/(5 \ "s}\right)$

$= \left(35 \setminus \text{m/s")/(5 \ "s}\right)$

$= 7 \setminus {\text{m/s}}^{2}$