A rigid ingot is pressed between two parallel guides moving in horizontal directions at opposite velocities `v_(1)` and `v_(2)`. At a certain instant of time, the points of contact between the ingot and the guides lie on a straight line perpendicular to the directions of velocities `v_(1)` and `v_(2)` (Fig). What points of teh ingot have velocities equal in magnitude to `v_(1)` and `v_(2)` at this instant ?