Under the ruler 3: tilting the ruler

Since some people say that I'm tilting the ruler to make the cart move right or left, a quick demonstration to show that this isn't the case.

Category:

Science & Technology

Tags:

• DWFTTW
• DDWFTTW
• newton
• physics
• mechanics
• wheels
• gears
• velocity
• experiment
• paper
• cotton reel
• tilting
• toys

[UTJhn]

As for keeping the cart still while moving the ruler and 'ground' (i.e. paper), I can think of one relatively simple solution. It would require building a second identical cart, and attach its frame to your table. The paper would go under the reels of both carts and the ruler would sit across both wheels. The fixed cart would provide the proper relative movements for the paper and ruler to keep the second cart stationary. As a bonus it would force the ruler horizontal as well.

[coolaun]

@UTJhn That's a very good idea. Unfortunately I don't have the elements to make a second identical cart: the cart was just made from bits and pieces I had around the house. Maybe I could find enough other bits and pieces to make a cart with the same dimensions.

[bobaduddle]

How come when I try this the wheels cancel out and it does not move? Then I tried tilting it and it worked

[coolaun]

If the wheels are "cancelling out" it's probably because there is little or no difference between the outside and inside radii of the cotton reels. Here, the inner radius of a cotton reel (where the blue wheel touches it) is approximately 1/2 that of the outside radius (where the reel touches the surface on which it rolls).

[skinnymcpenny]

Rate this commment a thumbs up if you want more vids AND his voice makes you sleepy :)

[pjuwmkp]

your voice is sooo relaxing. sometimes when i cant fall asleep i turn on the best of youtube podcast of ur video and it knocks me out lol.

[TomusMedia]

please do audio books!

[AlexRaato]

MIND == BLOWN

[wantapgt]

@Steviewonder74CEA it's just ignorance that causes most "fake" comments. It amuses me too. Instead of taking the time to use their mind to understand concepts, the ignorant just refuse to acknowledge the possibility and call "fake." Sad sad people.

[MrRubixTV]

@UTJhn.  Thnx, that really helps

[UTJhn]

@drawnasunder. Yes, if the wind cart has a 1 to 1 gear ratio (wheel rpm=prop rpm) then the prop pitch needs to be less than the wheel circumference. 1/2 the circumference to have the same ratio as the cart in this video. If the pitch and circumrference are equal, the same effect can be obtained with a 2 to 1 gear ratio such that wheel rpm= 2X prop rpm.

[UTJhn]

@MrRubixTV. I don't know if you are still seeking an answer, or if you are still checking here. If so, I hope this helps. The big wheel and the cotton reels counter rotate, so the big wheel must go against the ruler or the reels must go against the paper. Since the ruler is connected through the big wheel to the smaller diameter part of the reels, the paper has the leverage advantage and dictates the direction of rotation.

[steviewonder74CEA]

I find the fact that this has accusations of being fake very funny. If a person was going to lie... it wouldn't be about this.

[UTJhn]

@coolaun

Having the fixed cart look different might actually be good. The only critical thing is the radius ratio. Having the same height would be nice, but a tilted ruler can work (the tilt affects the ratio, but it is the same for both carts). Alternatives are a ruler with an offset parallel attachment, or a "ground" with a step in it. A stack of papers can provide a step of finely tuned height. The height of the cart itself could be adjusted some if the reel base length was variable.

[UTJhn]

@coolaun

Glad you liked the idea. Sorry you don't have the parts. That possibility had occured to me, but I dismissed it. The parts seemed like they should come in larger numbers.

An alternative would be to make 2 new carts, but I think the one you have has become an icon and it would be a shame not to continue with it.