# Question f33b1

Jun 10, 2017

color(blue)[v = 40 "m"/"s"

#### Explanation:

Since the body is falling under the influence of gravity (free fall), we can use the following equation to find the velocity at which the body will hit the ground

$\textcolor{w h i t e}{a a a a a a a a a a a a a a a a a a a} \textcolor{\mathmr{and} a n \ge}{v = \sqrt{2 h g}}$

Where
$\text{h = height at which the body falls with respect to some level (m)}$
$\text{g = gravitational acceleration constant} \left(9.8 \frac{m}{s} ^ 2\right)$

$\textcolor{w h i t e}{a a a}$

Plugin and solve (ignored units)

• $v = \sqrt{2 h g} \to v = \sqrt{2 \times 80 \times 9.8}$

• color(blue)[v = 40 "m"/"s"#

rounded to $1$ significant figure, the number given in the problem.