# Objects A and B are at the origin. If object A moves to (-8 ,-2 ) and object B moves to (5 ,3 ) over 3 s, what is the relative velocity of object B from the perspective of object A? Assume that all units are denominated in meters.

Apr 15, 2016

4.64 m/s

#### Explanation:

Because they both start at the same point, the final position distance divided by the time is the relative velocity.

The distance between the final point locations can be calculated from the “distance formula” for Cartesian Coordinate systems:
d= $\sqrt{{\left({x}_{2} - {x}_{1}\right)}^{2} + {\left({y}_{2} - {y}_{1}\right)}^{2}}$
d= $\sqrt{{\left(5 - - 8\right)}^{2} + {\left(3 - - 2\right)}^{2}}$
d= $\sqrt{{\left(13\right)}^{2} + {\left(5\right)}^{2}}$
d= $\sqrt{169 + 25}$
d= $\sqrt{194}$ = 13.9

13.9m/3s = 4.64 m/s