Question

Objects A and B are at the origin. If object A moves to `(5, -1)` and object B moves to `(-7, 8)` 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.

Answer 1

This one seems tougher than it really is. The two objects start together at a separation of `0` `m`, and end at a separation of `r=15` `m`, `3` `s` later. That means the relative velocity, `v=(Delta d)/(Delta t)=15/3=5` `ms^-1`.

Explanation:

To find the distance between the final positions of the objects:

`r=sqrt((x_2-x_1)^2+(y_2-y_1)^2)=sqrt((-7-5)^2+(8-(-1))^2)=sqrt(144+81)=15` `m`