JUST IMAGINE MY DISMAY....

[darmoose]

I as out in the yard playing with my grandson last evening (he"s six months old), and he says to me..."grandpa, watch this", to which he ran around the yard holding out his newly acquired little pinwheel toy (you know.. one of those spinny things on a stick).

wellll, there i was, watching the lil tyke run around, when lo and behold.... i realized the little spinny thing on a stick was actually spinning. in fact, the faster he ran, the faster the darn thing would spin.

i was dazed and bewildered, cause i had drank the coolaid, and had labored for the past six to eight months (my how time flys) under the belief that a spinny thing, when dragged thru the air (or water, i suppose) would just naturally remain still (very still) because doing so would create the least resistance (and would ,indeed, in so doing, allow for the greatest speed of the toy thru the air).

needless to say, i havent slept a wink since(pondering this dilema). can any of the wise old sages lurking on this austere board please explain why that lil spinny thing would actually spin rather than hold still when my six month old grandson was running around like that?

FWISF
darrell

[Carl Thunberg]

Simply stated "an object in motion stays in motion, an oject at rest stays at rest unless acted upon by another force." The pinwheel has to move because it has blades that are inclined to the flow of air. As the air impacts the blades it exerts a force. Newton's first law states that it must move, and in fact it matches every kid's observations since the pinwheel was invented.

Yes, this also applies to propellers. If the prop is free to rotate, then the force of water past the blades will cause the prop to rotate. I don't think anyone would question this. This fact of motion has no bearing on the fixed/free-wheeling prop debate, which I refuse to enter.

[carldoc]

I'm more impressed that he can walk and talk at 6 months.

[Dick Barthel]

Its summer man...don't you know that is a winter debate?

Dick

[darmoose]

i couldnt help thinking that the little spinny thing pinned to a stick was actually taking the "path of leastest resistance" through the air as it spun, (after all.. it didnt have to spin) while the lil tyke was running around the yard.

i asked the lil feller about this and he agreed that if the "path of leastest resistance" was for the spinny thing to remain still (very still), the spinny thing would surely do so.

ahh..well

FWISF

darrell