# What is the speed of an object that travels from (9,-6,1)  to (-1,3,-8)  over 4 s?

Jan 6, 2016

#### Answer:

$3.63 \text{units/s}$

#### Explanation:

The distance between the 2 points located in 3 space is given by:

$d = \sqrt{{\left[9 - \left(- 1\right)\right]}^{2} + {\left[- 6 + 3\right]}^{2} + {\left[1 - \left(- 8\right)\right]}^{2}}$

$\therefore d = \sqrt{{11}^{2} + {3}^{2} + {9}^{2}}$

$d = \sqrt{211} = 14.52 \text{units}$

$v = \frac{d}{t} = \frac{14.52}{4} = 3.63 \text{units/s}$