Final answer:
In washing machines, water is removed from clothes during the spin cycle due to the inertia of water particles, which makes them move in a straight path, while the drum moves circularly providing a centripetal force. The perceived centrifugal force by an observer rotating with the drum is fictitious and does not exist in an inertial frame of reference.
Step-by-step explanation:
Centrifugal Force and Water Extraction in Washing Machines
Regarding washing machines with cloth dryers, it's stated that "the centrifugal force throws the water particles away from the drum." This statement can be analyzed from two perspectives: an observer rotating with the drum (rotating frame of reference) and an observer standing still (inertial frame of reference).
For an observer rotating with the drum, it appears as though there is a fictitious force pushing the water particles outward. This is what we call the centrifugal force in the rotating frame of reference. However, in reality, this force does not exist. What actually happens is the water, due to its inertia, tends to continue moving in a straight line (tangent to the circular path). Since the drum is forcing the clothes and water in a circular path, this inertial tendency results in the water moving outward, relative to the rotating drum.
For an observer standing outside the machine, they would see the centripetal force, which is the real force provided by the walls of the spinning drum, directing the motion in a circular path. Because the water cannot follow this curved path due to its inertia, it moves straight out, away from the center of the circle, and is expelled through the drum’s perforations.
In a spin-dryer, the spinning creates a large angular velocity. This causes the water to be thrown out rapidly, thanks to its inertia, which is perceived as a centrifugal force effect in a rotating frame but is actually just the lack of a centripetal force to keep the water moving in a circle.