Question

In Lec On Velocity And Acceleration 1D Kinematics, in the first help session prof. asks whether the #2 ball is going up o down how to solve that?

Answer 1

take the time derivative of the second equation then substitute time of the hit and if you find that the velocity is negative then the #2 ball is going down because we've assumed the up direction of increasing values of y and v. In this case the velocity of that ball is approximately -2,33 m/s so it's going down