# Objects A and B are at the origin. If object A moves to (-2 ,8 ) and object B moves to (-5 ,-6 ) over 4 s, what is the relative velocity of object B from the perspective of object A?

Mar 1, 2016

#### Answer:

${\vec{v}}_{A B} = \frac{\sqrt{203}}{4} \frac{u n i t}{s}$

#### Explanation:

$\text{displacement between two point is:}$
$\Delta \vec{x} = - 5 - \left(- 2\right) = - 3 \text{ unit}$
$\Delta \vec{y} = - 6 - 8 = - 14 \text{ unit}$
Delta vec s=sqrt((-3)^2+(-14)^2))
$\Delta \vec{s} = \sqrt{9 + 194} = \sqrt{203}$
${\vec{v}}_{A B} = \frac{\Delta \vec{s}}{\Delta t}$
${\vec{v}}_{A B} = \frac{\sqrt{203}}{4} \frac{u n i t}{s}$