# What is the speed of an object that travels from ( 8,-4,2)  to ( 7,-3,6 )  over 3 s?

##### 1 Answer
Feb 29, 2016

$v = \sqrt{2} \frac{m}{s}$

#### Explanation:

$\text{Distance the point (8,-4,2) and (7,-3,6) may be calculated using:}$
$\Delta x = \sqrt{{\left(7 - 8\right)}^{2} + {\left(- 3 + 4\right)}^{2} + {\left(6 - 2\right)}^{2}} = \sqrt{1 + 1 + 16} = \sqrt{18} m$
$\text{The speed of an object is given by :} v = \frac{\Delta x}{t}$
$v = \frac{\sqrt{18}}{3}$
$v = \frac{\sqrt{9 \cdot 2}}{3}$
$v = 3 \cdot \frac{\sqrt{2}}{3}$
$v = \sqrt{2} \frac{m}{s}$