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Re: Hovercraft B/C
Posted: May 10th, 2017, 6:16 pm
by Ashernoel
ApprovedCargo91 wrote:Hey guys,
I'm kinda new around here so please excuse me if I'm breaking some sort of rule(s) by butting in here, but I've got a question about a question I just saw on a Hovercraft test. The question reads:
"A pipe carrying water at 20°C has a diameter of 2.5 cm. Estimate the maximum flow speed if the flow must be streamline as measured in cm/sec."
Everywhere I've looked online has stated that in order to find the value of the velocity of the water in the pipe, the volume or mass flow rate is also required, but I don't see how you'd derive that from the information given. Am I missing something in this question, or is it just a bad question? Thanks!
LOL that's a wright state test question. lol 20/2.5 = 8 lol
lol
Re: Hovercraft B/C
Posted: May 10th, 2017, 6:20 pm
by megapanda
Hey guys
I have some questions i hope you can answer for nationals
Do the airport security people cause any trouble with bringing your hovercraft as a carry on?
Do most teams have really precise, max weight hovercrafts? (how do you even make it that heavy
)
Can we practice on the track the day before the actual event?
Are we allowed to touch the hovercraft before it crosses or drop runs to count them as failed runs?
Do we get test/practice runs during our 8 mins?
Thanks so much!
Re: Hovercraft B/C
Posted: May 10th, 2017, 6:32 pm
by windu34
megapanda wrote:Hey guys
I have some questions i hope you can answer for nationals
Do the airport security people cause any trouble with bringing your hovercraft as a carry on?
Do most teams have really precise, max weight hovercrafts? (how do you even make it that heavy
)
Can we practice on the track the day before the actual event?
Are we allowed to touch the hovercraft before it crosses or drop runs to count them as failed runs?
Do we get test/practice runs during our 8 mins?
Thanks so much!
1.) Um YES! Do not risk it! "Don't worry its not a bomb" wont fly here
2.) Id say at least 1/3 (so 20 teams) will have max weight hovercrafts. Idk about how precise people will be. I'm curious about predictions about this as well
3.) No I highly doubt that
4.) Someone else please answer this. I know there was discussion about this and now I cant remember. I feel like the answer is no
5.) No
Re: Hovercraft B/C
Posted: May 10th, 2017, 7:19 pm
by RestingDoll
Ashernoel wrote:ApprovedCargo91 wrote:Hey guys,
I'm kinda new around here so please excuse me if I'm breaking some sort of rule(s) by butting in here, but I've got a question about a question I just saw on a Hovercraft test. The question reads:
"A pipe carrying water at 20°C has a diameter of 2.5 cm. Estimate the maximum flow speed if the flow must be streamline as measured in cm/sec."
Everywhere I've looked online has stated that in order to find the value of the velocity of the water in the pipe, the volume or mass flow rate is also required, but I don't see how you'd derive that from the information given. Am I missing something in this question, or is it just a bad question? Thanks!
LOL that's a wright state test question. lol 20/2.5 = 8 lol
lol
Uhh I think it's a bit more complicated lol.
Kinematic viscosity of water @20 C = 1.004e-6
Reynold's Number = velocity * diameter / viscosity
Streamlined Re = 2000 (This is interesting -- depending on the source it varies. 2000 gives you exactly 8.032 cm/s though.)
2000 = (v*.025)/(1.004e-6)
v=.8032 m/sec
v=8.032 cm/sec, sig fig ~~ 8.0 cm/sec
Re: Hovercraft B/C
Posted: May 10th, 2017, 7:26 pm
by ApprovedCargo91
RestingDoll wrote:
Uhh I think it's a bit more complicated lol.
Kinematic viscosity of water @20 C = 1.004e-6
Reynold's Number = velocity * diameter / viscosity
Streamlined Re = 2000 (This is interesting -- depending on the source it varies. 2000 gives you exactly 8.032 cm/s though.)
2000 = (v*.025)/(1.004e-6)
v=.8032 m/sec
v=8.032 cm/sec, sig fig ~~ 8.0 cm/sec
Woah, there's still much I don't know how to do apparently. Thanks for replying with the solution!
Re: Hovercraft B/C
Posted: May 10th, 2017, 8:15 pm
by Ashernoel
RestingDoll wrote:Ashernoel wrote:ApprovedCargo91 wrote:Hey guys,
I'm kinda new around here so please excuse me if I'm breaking some sort of rule(s) by butting in here, but I've got a question about a question I just saw on a Hovercraft test. The question reads:
"A pipe carrying water at 20°C has a diameter of 2.5 cm. Estimate the maximum flow speed if the flow must be streamline as measured in cm/sec."
Everywhere I've looked online has stated that in order to find the value of the velocity of the water in the pipe, the volume or mass flow rate is also required, but I don't see how you'd derive that from the information given. Am I missing something in this question, or is it just a bad question? Thanks!
LOL that's a wright state test question. lol 20/2.5 = 8 lol
lol
Uhh I think it's a bit more complicated lol.
Kinematic viscosity of water @20 C = 1.004e-6
Reynold's Number = velocity * diameter / viscosity
Streamlined Re = 2000 (This is interesting -- depending on the source it varies. 2000 gives you exactly 8.032 cm/s though.)
2000 = (v*.025)/(1.004e-6)
v=.8032 m/sec
v=8.032 cm/sec, sig fig ~~ 8.0 cm/sec
ah that makes sense. lol. not 20/2.5 xD lolllll
Re: Hovercraft B/C
Posted: May 10th, 2017, 9:07 pm
by Zioly
Ashernoel wrote:RestingDoll wrote:Ashernoel wrote:
LOL that's a wright state test question. lol 20/2.5 = 8 lol
lol
Uhh I think it's a bit more complicated lol.
Kinematic viscosity of water @20 C = 1.004e-6
Reynold's Number = velocity * diameter / viscosity
Streamlined Re = 2000 (This is interesting -- depending on the source it varies. 2000 gives you exactly 8.032 cm/s though.)
2000 = (v*.025)/(1.004e-6)
v=.8032 m/sec
v=8.032 cm/sec, sig fig ~~ 8.0 cm/sec
ah that makes sense. lol. not 20/2.5 xD lolllll
I'm so glad Div. B doesn't have to deal with these problems (or so the rules say...).
Re: Hovercraft B/C
Posted: May 12th, 2017, 11:57 am
by antoine_ego
I'm sad that we cannot know who's writing the test for Div C, because they aren't releasing event supervisors. It was nice back in the day when you could actually get an idea of a test writer's style by figuring out what Invites they ran and getting ahold of those tests.
Sad life
Re: Hovercraft B/C
Posted: May 12th, 2017, 1:29 pm
by Ionizer
Didn't they write the tests for Golden Gate and MIT?
From the Nationals thread:
antoine_ego wrote:windu34 wrote:kenniky wrote:The Hovercraft ES also supervised at MIT and Golden Gate I believe
This is for div c
The hovercraft supervisor did not supervise at golden gate
I believe the tests were written by the same people at both Golden Gate and MIT though.
Re: Hovercraft B/C
Posted: May 12th, 2017, 2:32 pm
by antoine_ego
Ionizer wrote:Didn't they write the tests for Golden Gate and MIT?
From the Nationals thread:
antoine_ego wrote:windu34 wrote:
The hovercraft supervisor did not supervise at golden gate
I believe the tests were written by the same people at both Golden Gate and MIT though.
I talked to the test writer at MIT. The official ES was a different guy from the test writer. The official one was also the one who brought in the tracks. We know he's going to be at Nats. However, we don't know if the MIT/Golden Gate test writer is the same guy writing at Nats.