# What is the speed of an object that travels from ( 8 , 4, 5 )  to ( 6 , -4, ,2 )  over 4 s?

Jun 21, 2017

The speed is $= 2.92 m {s}^{-} 1$

#### Explanation:

The distance is

$d = \sqrt{{\left(6 - 8\right)}^{2} + {\left(- 4 - 4\right)}^{2} + {\left(2 - 5\right)}^{2}}$

$= \sqrt{4 + 64 + 9}$

$= \sqrt{77}$

The time is $t = 4 s$

The speed is

$v = \frac{\sqrt{77}}{3} = 2.92 m {s}^{-} 1$