Question

Objects A and B are at the origin. If object A moves to `(-2 ,7 )` and object B moves to `(7 ,-5 )` 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

The relative velocity is `= <3, -4> ms^-1`

Explanation:

The absolute velocity of `A` is `v_A=1/3 <-2,7> = <-2/3, 7/3> ms^-1`

The absolute velocity of `B` is `v_B=1/3 <7,-5> = <7/3, -5/3> ms^-1`

The relative velocity of `B` with respect to `A` is

`v_(B//A)=v_B-v_A`

`=<7/3, -5/3> - <-2/3, 7/3>`

`= <7/3+2/3, -5/3 -7/3>`

`= <9/3, -12/3>`

`= <3, -4> ms^-1`