Objects A and B are at the origin. If object A moves to (2,7) and object B moves to (6,5) over 3s, what is the relative velocity of object B from the perspective of object A? Assume that all units are denominated in meters.

1 Answer
Mar 5, 2016

Initially both A and B were at origin O (0,0)
after 3sec A reaches at (-2,7) and B at (6,-5)
So displacement vector of A =2ˆi+7ˆj m
velocity vector of A, VA=13(2ˆi+7ˆj) m/s
displacement vector of B =6ˆi5ˆjm
velocity vector of B, VB=13(6ˆi5ˆj) m/s
So the relative velocity of B from the perspective of A is given by
VBA=VBVA=13((6+2)ˆi(5+7)ˆj)
=13(8ˆi12ˆj) m/s
VBA=1382+122=2083=4.81ms1