There is this square of side length $a$. It's opposite vertices are being pulled in opposite directions with a constant velocity $u$. The question here is what is the velocity of the remaining pair of opposite vertices?
I tried to use the rules of constrained motion and made the velocity of each point along one of the edges equal as there is no relative velocity along that line always. I ended up getting that the velocity of the remaining two vertices would also be $u$. But I then reminded myself that I completely neglected the role of the velocity of the opposite vertex (whose velocity is initially given) in calculating the velocity of the other pair of vertices. Then I tried to use center of mass concept as the center of mass is stationary but was confused how to plug in the various values.
I'm really confused and want somebody to help me out of this question. Thanks.