## Search found 77 matches

March 16th, 2012, 8:58 am
Forum: 2012 Build Events
Topic: Gravity Vehicle C
Replies: 805
Views: 74802

### Re: Gravity Vehicle C

What would be the problem with putting the mass behind the rear axle? Not completely behind it, but something like 3/4 of the mass.
March 15th, 2012, 8:12 am
Forum: 2012 Build Events
Topic: Gravity Vehicle C
Replies: 805
Views: 74802

### Re: Gravity Vehicle C

It can be moved left/right (about 7cm each direction). The paperclip can be moved along the bar (taped in position), over a distance of about 35cm. Our wheel circumference is about 18cm, which means an adjustment range of almost 1 rev, plus, and minus. Our brake system.....increments/is set to a pa...
March 11th, 2012, 2:12 pm
Forum: 2012 Build Events
Topic: Gravity Vehicle C
Replies: 805
Views: 74802

### Re: Gravity Vehicle C

i consulted a physics professor and did some calculations with him based on the curve of our ramp and the size of the vehicle; the calculations were all wrong; the estimated time was about 4.1 seconds, but our vehicle traveled the 10 meters in about 1.12 seconds. Pretty fast. O.O I give up. I can't...
March 4th, 2012, 10:57 am
Forum: 2012 Lab Events
Topic: Keep the Heat B/Thermodynamics C
Replies: 661
Views: 81077

### Re: Keep the Heat B/Thermodynamics C

It's that time of year again where those of us on the national rules committees start working on the rules for next year. As I've done in the past, I'm soliciting suggestions for rules changes for Keep the Heat / Thermodynamics. Please don't just say "I don't like XXXX", but rather make c...
February 24th, 2012, 4:21 pm
Forum: 2012 Lab Events
Topic: Forensics C
Replies: 204
Views: 41467

### Re: Forensics C

For the first invitational that I went to, the ES accepted both plastics because he didn't give any further information.
February 24th, 2012, 4:02 pm
Forum: 2012 Build Events
Topic: Robot Arm C
Replies: 531
Views: 54403

### Re: Robot Arm C

Has anyone had trouble with VEX motors sometimes not turning? I can hear a response in the motor, but it won't move. It will SOMETIMES randomly come back and start turning after I wiggle the joystick or push the button a few times or turn the controller off and on. Mostly it doesn't respond and I j...
February 24th, 2012, 1:55 pm
Forum: 2012 Build Events
Topic: Robot Arm C
Replies: 531
Views: 54403

### Re: Robot Arm C

Has anyone had trouble with VEX motors sometimes not turning? I can hear a response in the motor, but it won't move. It will SOMETIMES randomly come back and start turning after I wiggle the joystick or push the button a few times or turn the controller off and on. Mostly it doesn't respond and I ju...
February 13th, 2012, 1:33 pm
Forum: 2012 Build Events
Topic: Robot Arm C
Replies: 531
Views: 54403

### Re: Robot Arm C

How many motors are you guys using? We used 5 and got like 10th. Motors shouldn't matter for scoring that much, seeing as it's only a tiebreaker. We also are using 5. Ten bucks the national champion uses only three. I agree, but I'm assuming most teams aren't going to be vying for the top spot at n...
February 13th, 2012, 3:50 am
Forum: Helicopters C
Topic: Duration
Replies: 219
Views: 25306

### Re: Duration

Apparently the top score at the invitational I was at this weekend was 224 seconds (3 min 44 sec)

I don't know if they had a Chinook design, but if they did, that's still 1 min 14.7 seconds.

All the top 6 scores were above a minute 30 sec
February 13th, 2012, 3:44 am
Forum: 2012 Build Events
Topic: Robot Arm C
Replies: 531
Views: 54403

### Re: Robot Arm C

JohnHa wrote:How many motors are you guys using? We used 5 and got like 10th.

Motors shouldn't matter for scoring that much, seeing as it's only a tiebreaker. We also are using 5.
February 10th, 2012, 5:12 am
Forum: 2012 Lab Events
Topic: Keep the Heat B/Thermodynamics C
Replies: 661
Views: 81077

### Re: Keep the Heat B/Thermodynamics C

Thanks for the help. Now, onto boxes. Has anyone tried the box within a box technique? If so, did you surround the smaller box with insulating materials, or just keep in open? Several teams at my school have done one or the other with mixed success. My device is a box in a box. I don't have better ...
February 9th, 2012, 3:12 am
Forum: 2012 Lab Events
Topic: Forensics C
Replies: 204
Views: 41467

### Re: Forensics C

I'm having trouble identifying plastics. Is it difficult to create your own ~40% iso. alcohol or 10% NaCl and I'm just not getting the right solutions? I've had PETE float in my 10% NaCl water solution. Or is there a certain way to test it that makes the difference? Do you drop the plastic in, or do...
February 1st, 2012, 5:45 am
Forum: 2012 Lab Events
Topic: Keep the Heat B/Thermodynamics C
Replies: 661
Views: 81077

### Re: Keep the Heat B/Thermodynamics C

questionguy wrote:would that mean that the max distance between the beaker and top of device (assuming it is a cube) have to be <5 cm?

That's what I've interpreted it to be. I think it was addressed earlier in the thread; it's supposed to accommodate for smaller thermometers or something
January 31st, 2012, 6:50 pm
Forum: 2012 Lab Events
Topic: Forensics C
Replies: 204
Views: 41467

### Re: Forensics C

In my experience, soil analysis has been mostly common sense: this suspect is a beach lifeguard, and very sandy soil was found at the crime scene, so that implicates him. Potting soil was found at the crime scene, and this one works in a greenhouse. Things like that. On some events, they might conc...
January 31st, 2012, 6:37 pm
Forum: 2012 Build Events
Topic: Gravity Vehicle C
Replies: 805
Views: 74802

### Re: Gravity Vehicle C

I am confused with the rules when it says an automatic release device on the ramp. What is an example of this I just really dont get how that works. Mine is a 'u' shaped out of metal and put through the back of the ramp. The 'tongs' protrude from the ramp, and I sit the car on the 'tongs'. I use th...