# Objects A and B are at the origin. If object A moves to (-2 ,7 ) and object B moves to (5 ,3 ) over 4 s, what is the relative velocity of object B from the perspective of object A?

Mar 3, 2016

$\left(\begin{matrix}\frac{7}{4} \\ - 1\end{matrix}\right) \text{unit/s}$

#### Explanation:

After $4 \text{s}$, $A$ observes that $B$ is at

$5 - \left(- 2\right) = 7$

7 units in the positive $x$ direction and

$3 - 7 = - 4$

4 units in the negative $y$ direction relative to itself.

The $x$ component of the velocity of $B$ relative to $A$ is $\frac{7}{4} \text{unit/s}$

The $y$ component of the velocity of $B$ relative to $A$ is $- 1 \text{unit/s}$