Air Trajectory B/C

[bearasauras]

I didn't write these rules, but as an engineer, I would do exaclty what SPP SciO said and do charts of mass height vs distance instead of going through the force.

[asthedeer]

Just received my copy of the rules yesterday.

Alright......so someone please tell me that the 0.1cm distances for Nationals is a misprint. Like seriously, how are event proctors going to measure that?

Darnit... good catch. It should be 0.1m (or 10cm). Just goes to show that no matter how many sets of eyes we have on the rules, simple things like this slip through the cracks. I'll get a rules clarification posted ASAP.

Thank you! My coach also submitted a question about that to the National SciOly people. Hah....I was hoping that'd be a mistake......

[daycd]

I'm just stating the point of the graphs from the rule writers prospective; we are supposed to be using actual physics

I'd actually be surprised if this was their goal. I think the reason they want multiple graphs is so that each team has to test different parameters. Changes to the angle of the barrel, the height of the barrel, the mass of the weight etc. will change the range and accuracy of the shots. So to have four graphs as a minimum means that each team has experimented with some variables. But that is quite different to making a prediction based on physics and then seeing if the prediction hold true.

[windu34]

I'm just stating the point of the graphs from the rule writers prospective; we are supposed to be using actual physics

I'd actually be surprised if this was their goal. I think the reason they want multiple graphs is so that each team has to test different parameters. Changes to the angle of the barrel, the height of the barrel, the mass of the weight etc. will change the range and accuracy of the shots. So to have four graphs as a minimum means that each team has experimented with some variables. But that is quite different to making a prediction based on physics and then seeing if the prediction hold true.

My Interpretation:
The job of the rules comittee isnt to "assign" work for us to do. Their job is to set the goal and we are to do whatever is neccessary to achieve that goal whether it be 100s of hours or 10 hours.
What sets scioly and school apart is responsibility: We are responsible in Scioly - we are responsible for teaching ourselves concepts, giving ourselves homework, etc
In school, the teachers are responsible for teaching us concepts and giving out homework.
Scioly's purpose is to allow students who succeed without a whole lot of effort in school to find a community that challenges them.
With this in mind, the graphs can't possibly be meant to be a "homework" assignment that makes sure students do their work - teams can just put random info in it and easily do well at competition. The purpose of the graphs is to encourage us to teach ourselves physics and learn how to plot acceleration vs time vs velocity or whatever other variables that apply to your device.

[SPP SciO]

Any plans on how to adapt to the size restrictions? Also what kind of pvc do you use? Thin walled?

Curious about this also - our team grabbed some of these http://www.amazon.com/IZZO-Golf-C10315- ... B00BSV7QV6 for projectiles. However, they're slightly larger than ping pong balls, which fit pretty well in 1-1/2 sch 40 pvc. Maybe thin-walled 1-1/2 would accommodate golf balls better? This seems like a good resource: https://flexpvc.com/

[laidlawe18]

Any plans on how to adapt to the size restrictions? Also what kind of pvc do you use? Thin walled?

Curious about this also - our team grabbed some of these http://www.amazon.com/IZZO-Golf-C10315- ... B00BSV7QV6 for projectiles. However, they're slightly larger than ping pong balls, which fit pretty well in 1-1/2 sch 40 pvc. Maybe thin-walled 1-1/2 would accommodate golf balls better? This seems like a good resource: https://flexpvc.com/

I also am looking into golf balls. Assuming you already have the golf balls, could you share a little about them? Like how much they weigh, whether they're squishy or not, etc. I think that now that foam golf balls are allowed, I'd like to find one that is relatively dense to increase consistency.

[daycd]

The purpose of the graphs is to encourage us to teach ourselves physics and learn how to plot acceleration vs time vs velocity or whatever other variables that apply to your device.

I guess we disagree here. I see the purpose of the graphs as a way to encourage us to experiment with the variables. I really don't see how they direct us down the physics route. Certainly the physics is not necessary to succeed.

We had graphs with 'height of weight vs distance' plotted. The variables between the different graphs we made were angle of the barrel, mass dropped and we used two different balls. So no velocity, time or acceleration at all.

[windu34]

The purpose of the graphs is to encourage us to teach ourselves physics and learn how to plot acceleration vs time vs velocity or whatever other variables that apply to your device.

I guess we disagree here. I see the purpose of the graphs as a way to encourage us to experiment with the variables. I really don't see how they direct us down the physics route. Certainly the physics is not necessary to succeed.

We had graphs with 'height of weight vs distance' plotted. The variables between the different graphs we made were angle of the barrel, mass dropped and we used two different balls. So no velocity, time or acceleration at all.

I know that. Most teams (likely all) wont use the graphs the way I stated. I didnt use them either. Im just stating what i believe to be the purpose. Its likely nobody at nats used the graphs the way i described

[SPP SciO]

...could you share a little about them? Like how much they weigh, whether they're squishy or not, etc.

They're a little more massive than a ping pong ball, but less so than a regular golf ball - maybe about 10 grams? We haven't done much experimenting with them yet. They're definitely squishy, and they rebound without any noticeable deformity, even after a strong squish. And, they bounce great off floors, walls ... If you use these, don't be surprised if your team starts playing all sorts of games with them, because they are a lot of fun. My favorite advantage over a ping pong ball though: they're super quiet!

[daycd]

Im just stating what i believe to be the purpose. Its likely nobody at nats used the graphs the way i described

Right, I understand. This is why I said we disagree. But that is OK

I just got the new rules and there is a little less room to make adjustments between shots. And less height to drop the weight. I'm pretty sure our design from last year will not work with the rule changes. I guess that is their intent.