Note: This discussion question is from my University Textbook, as it so happens you can only get the solutions to half of the odd numbered exercise questions... :grumpy: Disclaimer: I have been trying to wrap my head around this answer for a good 5 hours now, so it's not like I'm coming here to be spoon fed. Anyway, the question: "What is the purpose of the spin cycle of a washing machine? Explain in terms of acceleration components" My answer: The purpose of a spin cycle of a washing machine is to remove water from clothes. The drum of radius, r, rotating with speed, v, will have a centripetal acceleration a = V^2/r which is provided by a centripetal force, acting toward the centre of the drum, which in turn has an equal and opposite reaction (centrifugal?) force. The inertia of the clothes and the water particles causes them to keep moving in a straight line, that with the combination of the reaction force, causes them to move around the edge of the drum and the water particles move out through the holes in the drum, which then fly off at a tangent to the drum's rotation. ----------------- But then I watched this lecture from MIT and he explained a similar situation with water particles in a test tube and said that they experience no centripetal force: Please watch from 17:30 to 19:06 Immediately after he then does an identical experiment to my question (lettuce in a siv) and links it to his previous explanation. So now I feel like an idiot, even though he has gone through almost a identical experiment I can not find a way to intuitively explain what is happening. If anyone could talk me through this I would greatly appreciate it. I have 25 more lecture topics from this past semester to fully understand before the end of the christmas break!