Question

Objects A and B are at the origin. If object A moves to `(-7 ,2 )` and object B moves to `(-5 ,-6 )` over `2 s`, what is the relative velocity of object B from the perspective of object A?

Answer 1

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

Explanation:

The time is `t=2s`

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

The absolute velocity of `B` is `v_B=1/2* <-5, -6> = <-5/2, -3>`

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

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

`= <-5/2, -3> - <-7/2, 1>`

`= <-5/2-(-7/2), -3-(1) >`

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