Search found 1857 matches

RETURN_TO_SEARCH_ADV

by iwonder
August 12th, 2016, 10:35 am
Forum: Posting Games
Topic: Your Daily Random Comment
Replies: 23939
Views: 1317083

Re: Your Daily Random Comment

zyzzyva980 wrote:
Entomology wrote:Found this gem while browsing through a really old rocks and minerals binder:

Look at the date and the logo
Image





am I old now


I was in highschool... Competing in SO...
by iwonder
July 25th, 2016, 10:07 am
Forum: 2016 Invitationals, Regionals, and States
Topic: Texas 2016
Replies: 89
Views: 16192

Re: Texas 2016

As a competitor from Boca, Ill share our reasoning. We went to Cyfalls last year because it was an early tournament (Nov 3 I think) that was relatively competitive. That was pretty much the only reason we went. We are going to the Cornell invite instead of cyfalls because they moved their tournamen...
by iwonder
April 27th, 2016, 9:23 pm
Forum: 2016 Invitationals, Regionals, and States
Topic: Appeal to Nationals on State decision
Replies: 16
Views: 3353

Re: Appeal to Nationals on State decision

sciolyfan, word of advice. Work as hard as you can. Do as much as you can do. Give zero, zero, cares about what happens to other people. And do not, do not feel the inclination to police a scioly tournament. It's not your job, you've got better things to do. (Like beat them the old fashioned way).
by iwonder
April 2nd, 2016, 11:30 am
Forum: Posting Games
Topic: SciOly Assassination 106: Curtain Call
Replies: 210
Views: 19173

Re: SciOly Assassination 106: Curtain Call

Jaol wrote:Aww, i might be a bit late on this, but I think this might be a solution to the clue. Hmm let's see.


Lol you're never going to give it up are you? But you know the rules and so do I. Don't tell me you're too blind to see it. You know the game and you've got to play it.
by iwonder
March 26th, 2016, 10:32 am
Forum: Electric Vehicle C
Topic: Motor Breaking HELP
Replies: 23
Views: 2964

Re: Motor Breaking HELP

Alright, fine. One axle has a wingnut brake, the other has a motor, that's what we're talking about, right? There's already some sort of switch to turn off the motor. Using that switch, remove the battery and put say a 3-5 ohm resistor across it instead. The motor wouldn't 'slam on' the brakes, beca...
by iwonder
March 25th, 2016, 6:41 pm
Forum: Electric Vehicle C
Topic: Motor Breaking HELP
Replies: 23
Views: 2964

Re: Motor Breaking HELP

Braking with both axles should help because there will be more contact with the floor thus the coefficient of friction should be increased No thats not why. The coefficient of friction depends only on the material, not contact area. But friction force is friction coefficient times normal force so y...
by iwonder
March 24th, 2016, 8:45 am
Forum: Electric Vehicle C
Topic: Motor Breaking HELP
Replies: 23
Views: 2964

Re: Motor Breaking HELP

Bazinga+ wrote:
iwonder wrote:The way it sounds you're only using 1 of 2 axles to brake right now, anything you can do to brake with both axles will help dramatically.

Would it? In theory it shouldn't.


How wouldn't it?
by iwonder
March 22nd, 2016, 8:24 pm
Forum: Electric Vehicle C
Topic: EV Scores at Nationals
Replies: 20
Views: 3075

Re: EV Scores at Nationals

Rules clarification allows vehicles to go backwards. Just saying. Personally, if I were an ES for this I would put a wall 1m after the line. It's an interesting solution but there's no guarantee of space to do it in. Planning on it or making arguments that try to supplant math/physics calculations ...
by iwonder
March 22nd, 2016, 8:20 pm
Forum: Electric Vehicle C
Topic: Motor Breaking HELP
Replies: 23
Views: 2964

Re: Motor Breaking HELP

The capacitor is an interesting idea, it'd need to be very large, but it might work well. You could also probably set up the switch (double throw) to short the motor together when it's enabled, shorting the motor will make it act like a brake for smaller DC motors (large motors will need a resistor ...
by iwonder
March 22nd, 2016, 8:34 am
Forum: Electric Vehicle C
Topic: EV Scores at Nationals
Replies: 20
Views: 3075

Re: EV Scores at Nationals

Under ideal conditions: ⋅ 9 meters distance ⋅ wheels with µ = 1.0 tires ⋅ motor(s) supplying maximum necessary torque from zero to top vehicle speed Your device would accelerate from distance = 0 to 4.5 m at µ * g = 9.8 m/s² then at -9.8 m/s² from distance = 4.5 m to 0...
by iwonder
February 15th, 2016, 7:19 pm
Forum: Air Trajectory B/C
Topic: Rules contradiction?
Replies: 22
Views: 3176

Re: Rules contradiction?

You've asked 'clear' questions. They've been answered. You refuse to accept those answers. It's quite simple. I see no reason to take this much further.
by iwonder
February 12th, 2016, 5:48 am
Forum: Electric Vehicle C
Topic: Threshold for a competitive time
Replies: 14
Views: 2065

Re: Threshold for a competitive time

Increasing mass does increase the frictional force but it wont increase the max acceleration. From my research the greatest traction you can get with a gym floor with any material is .5-.6. There are some great wheels like Dr.fizzix high traction wheels (http://www.docfizzix.com/products/bulk-speci...
by iwonder
February 11th, 2016, 8:38 pm
Forum: Electric Vehicle C
Topic: Threshold for a competitive time
Replies: 14
Views: 2065

Re: Threshold for a competitive time

Yeah, sure, there's a reason jet dragsters are incredibly fast, but I assume it's very very hard to make a highly efficient and symmetric/reversible way to move air that fast. He might be able to speed up to that point but he couldn't slow back down as fast. What you need to do is devise a way to ga...
by iwonder
February 9th, 2016, 6:50 pm
Forum: Electric Vehicle C
Topic: Electric Vehicle C
Replies: 229
Views: 34036

Re: Electric Vehicle C

Brushless motors require three different 'PWM' signals all 120 degrees out of phase from the other. To get a reliable speed control you need to worry about correctly commutating the motor and some sort of speed detection (via sensor or back-emf measurement). I'm not even sure if the arduino uno has ...
by iwonder
February 5th, 2016, 4:38 am
Forum: Electric Vehicle C
Topic: Running EV help
Replies: 4
Views: 1100

Re: Running EV help

Well as we said, it's a judgement call by the supervisor on the day. In my opinion acetone would be just fine, and I've used that technique in multiple competitions and many gym floors without issue. Regardless, stopping the, before they used it was the right thing to do. The rest of the discussion ...

RETURN_TO_SEARCH_ADV