Hovercraft B/C

[Ashernoel]

There's a good chance that the mass score will be the same (25) for multiple teams that max out at 2kg. The chance of the time score being the same for more than one team is almost zero. Photogates can record a time to 5 digits, so the chance of two teams having the exact same time score is very small.

That's true, as there is obviously a certain level of deviation from the target time, but that deviation would be very similar among top-tier at nationals, which would mean the most distinguishing factor between competitors would be on the test score?

Or is it harder to calibrate a hovercraft than I'm thinking? Also, at the past two invitationals I've been to, they've all called target times by the second. Any guesses on how much higher level competitions will make the target time more precise, like with Air Trajectory and Scrambler?

It's hard to find a reliable, accurate method to change speed from my experience.
Also, the test is critical - I've won second in all my competitions with an awful hovercraft because I understand basic kinematics .

Did you try the potentiometer? literally for us it doesn't work :/

[chalker]

There's a good chance that the mass score will be the same (25) for multiple teams that max out at 2kg. The chance of the time score being the same for more than one team is almost zero. Photogates can record a time to 5 digits, so the chance of two teams having the exact same time score is very small.

That's true, as there is obviously a certain level of deviation from the target time, but that deviation would be very similar among top-tier at nationals, which would mean the most distinguishing factor between competitors would be on the test score?

Note that Hovercraft is a Physics committee event, and like all Physics committee events, we want there to be equal focus on theory and practice. The test score is worth half the potential points ON PURPOSE. Far too many competitors focus way too much on the device only to bomb the test. In general, I expect the top teams at Nationals to excel on both the test and the device portions.

[antoine_ego]

There's a good chance that the mass score will be the same (25) for multiple teams that max out at 2kg. The chance of the time score being the same for more than one team is almost zero. Photogates can record a time to 5 digits, so the chance of two teams having the exact same time score is very small.

That's true, as there is obviously a certain level of deviation from the target time, but that deviation would be very similar among top-tier at nationals, which would mean the most distinguishing factor between competitors would be on the test score?

Note that Hovercraft is a Physics committee event, and like all Physics committee events, we want there to be equal focus on theory and practice. The test score is worth half the potential points ON PURPOSE. Far too many competitors focus way too much on the device only to bomb the test. In general, I expect the top teams at Nationals to excel on both the test and the device portions.

For example, at MIT, I got a grand total of 34 points for the hovercraft itself (~25 weight, ~9 for speed), but our test score brought us up to 8th place.

[Tesel]

That's true, as there is obviously a certain level of deviation from the target time, but that deviation would be very similar among top-tier at nationals, which would mean the most distinguishing factor between competitors would be on the test score?

Note that Hovercraft is a Physics committee event, and like all Physics committee events, we want there to be equal focus on theory and practice. The test score is worth half the potential points ON PURPOSE. Far too many competitors focus way too much on the device only to bomb the test. In general, I expect the top teams at Nationals to excel on both the test and the device portions.

For example, at MIT, I got a grand total of 34 points for the hovercraft itself (~25 weight, ~9 for speed), but our test score brought us up to 8th place.

Yep. At Frankenmuth (nowhere near as hard as MIT, but one of the more competitive in MI) we got less than 20 points on the hovercraft, but our test got us up to 2nd. Plus, a lot of teams don't have good hovercrafts at all. Lesson is, make sure you study fluid dynamics and hovercraft history, since those two sections are a lot of points and will take a lot less time to do well than just the hovercraft.

[freed2003]

Can someone help me with this question?
A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28-degrees above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the long-jumper.

[Unome]

Can someone help me with this question?
A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28-degrees above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the long-jumper.

There are formulas for all of these which are commonly taught in physics classes (I don't know them off the top of my head). You can also derive them from general equations involving gravity and Newton's Laws. They all in general involve using sine and cosine to calculate the vertical and horizontal components, respectively, of the jumper's velocity.

[freed2003]

Do you know the formula? I couldn't find a suitable one on here:https://secure-media.collegeboard.org/d ... -table.pdf

[Adi1008]

Do you know the formula? I couldn't find a suitable one on here:https://secure-media.collegeboard.org/d ... -table.pdf

Look on wikipedia

[dcrxcode]

That's true, as there is obviously a certain level of deviation from the target time, but that deviation would be very similar among top-tier at nationals, which would mean the most distinguishing factor between competitors would be on the test score?

Or is it harder to calibrate a hovercraft than I'm thinking? Also, at the past two invitationals I've been to, they've all called target times by the second. Any guesses on how much higher level competitions will make the target time more precise, like with Air Trajectory and Scrambler?

It's hard to find a reliable, accurate method to change speed from my experience.
Also, the test is critical - I've won second in all my competitions with an awful hovercraft because I understand basic kinematics .

Did you try the potentiometer? literally for us it doesn't work :/

Yeah, we have a slide scale potentiometer from digikey rated for 5 ohms and 50 W and it works pretty well.

[Tesel]

It's hard to find a reliable, accurate method to change speed from my experience.
Also, the test is critical - I've won second in all my competitions with an awful hovercraft because I understand basic kinematics .

Did you try the potentiometer? literally for us it doesn't work :/

Yeah, we have a slide scale potentiometer from digikey rated for 5 ohms and 50 W and it works pretty well.

Mind sending us the link? We found a cheap one but it barely worked. For regionals in 2 weeks, we will just be swapping out fixed resistors, 0.25, 0.5, 0.75, 1.0, 1.5, and 2.0 ohm. That should be enough to get 1st in the region since we have done really well on all the practice tests and invitationals. However I think we need an actual sliding resistor to do well at states and I am hoping to have one by then. Thanks!