Question

Objects A and B are at the origin. If object A moves to `(-7 ,3 )` and object B moves to `(-6 ,2 )` 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

Given
`A" moves from "(0,0)->(-7,3)`
So displacement of A during 3 s

`vecd_A=(-7hati+3hatj)m`

So velocity of A

`vecv_A=vecd_A/3=(-7/3hati+hatj)m/s`

`B" moves from "(0,0)->(-6,2)`

So displacement of B during 3 s

`vecd_B=(-6hati+2hatj)m`

So velocity of A

`vecv_B=vecd_A/3=-2hati+2/3hatj`

Then the relative velocity of object B from the perspective of object A
`vecv_B-vecv_A=(-6+7/3)hati+(2/3-1)hatj`
`=-(11/3hati+1/3hatj)m/s`