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Ice_Phoenix87
March 2nd, 2004, 11:35 PM
I dont know if this is in the right area but i will ask anyway!! if it surposed to be in another area can you tell me. I was wondering how come the clothes in a washing machine when going thou the spin drying stage go around on the outside part and not around the bit in the middle? i got asked it today in physics. thanx for you help

fafalone
March 2nd, 2004, 11:44 PM
Short answer, centripetal force pushes it out.

Long answer, the second derivative of the position vector for an object moving in a circle always yields an acceleration towards the center; and the force is felt opposite to direction of acceleration (when you brake in a car, you feel like you're being pushed forward even though you're slowing down).

JaKiri
March 3rd, 2004, 5:24 AM
fafalone said in post # (http://www.scienceforums.net/forums/showthread.php?s=&postid=41473#post41473):
Short answer, centripetal force pushes it out.

Wrong cause and effect. It's the tendency to keep moving in a straight line that causes it, the centripetal force is the reaction force from the outside that causes it to orbit the centre.

mooeypoo
March 3rd, 2004, 5:23 PM
MrL_JaKiri,

I fail to see why fafalone was wrong and where your explanation is not exactly what he said, actually... :\

can you explain please?

-Demosthenes-
March 3rd, 2004, 6:36 PM
I see it. Centripetal force isn't the same as inertia mooeypoo.

mooeypoo
March 3rd, 2004, 7:36 PM
Yeah I know that. But I always thought that Centripetal force already included inertia in it... if you don't move something with "enough" inertia it won't really work..

I might be wrong here, that was my understanding though.

YT2095
March 4th, 2004, 1:08 AM
it works on the same principal as a centrifuge. or that trick when you spin a bucket of water around over you head and non comes out. btw, what`s the difference between centrifugal force and centripetal force?

mooeypoo
March 4th, 2004, 7:11 AM
That's what I was thinking.. isn't Centrifugal force already contain the inertia?? you can't have a centrifuce WITHOUT inertia... I was... always certain it just comes together :\

~moo

fafalone
March 4th, 2004, 8:18 AM
MrL_JaKiri said in post # (http://www.scienceforums.net/forums/showthread.php?s=&postid=41495#post41495):


Wrong cause and effect. It's the tendency to keep moving in a straight line that causes it, the centripetal force is the reaction force from the outside that causes it to orbit the centre.

Not quite.

swansont
April 2nd, 2004, 3:39 PM
I fail to see why fafalone was wrong and where your explanation is not exactly what he said, actually... :\


centripetal = "center seeking" A centripetal force can't push something away from the center.

As for the original question: in the middle of the washer, there is no force that would make the clothes go in a circle. That force is provided by the walls of the machine.

aman
April 2nd, 2004, 5:46 PM
In a weightless enviroment the acceleration induced would glue the clothes to the drum. Because of gravity it falls at dryer speed across the center which is most efficient for drying. The only way to have the clothes stay in the center would be to have no gravity and no acceleration.
Just aman

swansont
April 2nd, 2004, 6:54 PM
In a weightless enviroment the acceleration induced would glue the clothes to the drum. Because of gravity it falls at dryer speed across the center which is most efficient for drying. The only way to have the clothes stay in the center would be to have no gravity and no acceleration.
Just aman

For a dryer. But the discussion is about washing machines, so the spin axis is perpendicular to the surface of the earth. Gravity is irrelevant to the discussion.

Sayonara³
April 3rd, 2004, 3:43 AM
Only if it's a washer with a vertical drum.

My washer has a horizontal drum - use mine if you like.