1. The problem statement, all variables and given/known data Suppose a very light ball is thrown at a wall. The wall may be thought of as an xy-plane. At the moment the ball hits the wall, does it have 0 velocity in the x, y and z directions? Is drag on the ball (in each respective direction) small enough to be ignored at the moment the ball hits the wall? 2. Relevant equations D ~ (Av^2)/4 3. The attempt at a solution I think the ball momentarily has 0 velocity in the z-axis since the ball is changing direction along this axis. I think the ball will be slowed in the x and y axes at the moment it hits the wall, but its velocity in these directions will not equal zero at that instant. Therefore, drag can only be ignored in the z-direction.