Question

Objects A and B are at the origin. If object A moves to `(-4 ,-9 )` and object B moves to `(5 ,8 )` over `8 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 `= <9/8, 17/8> ms^-1`

Explanation:

The absolute velocity of `A` is `v_A=1/8 <-4, -9 > = <-1/2, -9/8> ms^-1`

The absolute velocity of `B` is `v_B=1/8 <5, 8 > = <5/8, 1> ms^-1`

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

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

`= <5/8, 1> - <-1/2, -9/8>`

`= <5/8+1/2, 1+9/8>`

`= <9/8, 17/8> ms^-1`