Question

Objects A and B are at the origin. If object A moves to `(-4 ,-4 )` and object B moves to `(2 ,-6 )` over `4 s`, what is the relative velocity of object B from the perspective of object A?

Answer 1

The relative velocity is `v_(B//A)=1.5veci-0.5vecj`

Explanation:

The absolute velocity of `A` is

`vecv_A=1/4<-4,-4>=<-1,-1>`

The absolute velocity of `B` is

`vecv_B=1/4<2,-6> = <1/2,-3/2>`

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

`vecv_(B//A)=vecv_B-vecv_A`

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

`=<3/2,-1/2> ms^-1`