Final answer:
When you remove the plug from a tube, water flows downward due to gravity. The rotation seen in drainage is usually caused by toilet water jets, not the Coriolis effect. During a washing machine's spin cycle, the centripetal force removes water from clothes.
Step-by-step explanation:
If you remove the plug from the tube, the water flow will be directed downward due to gravity. This is because when the barrier that is holding back the water is removed, gravity will pull the water towards the lowest possible point. The rotation of the water, seen in some cases like toilet flushes, is often caused not by the Coriolis effect in the Northern Hemisphere, but by the design of the toilet's water jets. In the absence of directional jets or any other introduced forces, rotation can arise from slight perturbations and the conservation of angular momentum, however, this effect is too weak to be noticed in household drains and toilets. Should water be forced up a drain, the rotation would not necessarily reverse; it would be determined by the direction of the applied force pushing the water.
Regarding washing machines, there is indeed a real force acting during the spin cycle; it is the centripetal force that causes water to move outward and away from the clothes, effectively removing the water due to the high-speed rotation. The same principle applies to any object moving in a circular path; the force is directed towards the center of the circle, but the inertia of the water (its tendency to move straight) causes it to be thrown outward and removed from the clothes.