## Wednesday, October 19, 2011

### Capstone Proposals: Feedback wanted!

The AP Physics class is working on their first set of capstone project proposals.  These are more independent explorations that show a student's ability to synthesize concepts, formulate questions, and apply physics in "real world" scenarios.  The final product will be narrative summaries of the design, results, and interpretation; we'll post those for feedback and revision as well.

Here's where you come in: these are draft proposals, and need feedback.  There are great ideas here, but they need focus, specificity, and a devil's advocate about measurement and design issues.  Comment early, comment often!

The draft proposals, in no particular order:
• Kati:
• Will hitting a field hockey ball with no follow through affect the motion? Will how far I follow through affect the motion of the ball? Will the ball accelerate more? I plan to test the velocity of the ball with and without a follow through. Then see if there is a greater acceleration with more follow through.
• the first swing in this video is what I will do but I will not be in motion.
• Alex C:
• My capstone will be analyzing the physics of the computer game Osmos.  In this game, a mass accelerates by 'shooting' part of its mass in the opposite direction.  I am going to analyze whether these separations agree with the conservation of momentum.  I will also being seeing if they do this in one, two, or three dimensions.
• Alex K:
• In the 2007 X-Games, skateboarder Jake Brown was launched 50 feet into the air, lost his skateboard in flight, and consequently slammed onto the flat of the ramp. I want to calculate the acceleration of his head in order for it to come to rest. From the various videos, I know the maximum height in which he reaches, and I can find his velocity. I can therefore find his velocity just before contact.
• To find his velocity, logger pro will be used. Using toolbox equations I can calculate his final velocity just before he hits the ground. I can then model his (non-constant) acceleration using logger and find a function of the acceleration of his head.
• Mike:
• I have two ideas for capstones. One is to determine how far down the pellet from my air rifle will drop when aiming for a target that is 100m away, then use this data to determine how much higher above the target I would have to aim when the scope is calibrated for 30m to hit a target is 100m away.
• Second is to determine which of my kicks a roundhouse, side, front, axe, back, jumping roundhouse, jumping side, jumping front, or jumping back kick exerts the most force. I would determine this by taking the average force between 3 of the same type of kick on a punching bag.
• I would appreciate your feedback.
• Toru:
• In an iphone app called “Tiny Tower”, there exists a ridiculous elevator. This “Infini-Lift Lightspeed”  elevator has an extreme acceleration rate that can injure the rider when it tries to stop. I will find the acceleration value and the force on the rider by scaling this app to the real world. With the newly found, I will find the movement of the rider when the elevator comes to a complete stop.
• The link to the video that shows how fast the elevator moves
• Cam:
• For my capstone project, I will build a roller coaster on Roller Coaster Tycoon, and graph the acceleration and position of the rollercoaster based on the velocity which is given.  I would build a simple wooden roller coaster that consists of a chain hill that goes into a steep drop, goes up a steep hill, takes a 180 degree turn and go back down the steep hill, go up 2-3 smaller steep hills based on how long the chain lift is.  The coaster will then take one last 180 degree turn and then head straight into the station.  With knowing the acceleration and velocity of the roller coaster, I will try to determine how long the roller coaster is by using kinematic equations to find the delta X of the roller coaster.  I will be able to check my answer by looking at the data page of the roller coaster, which lists the ride length among other things.
• Brandon:
• The defensive lineman hits an average joe. The footage I will be using is on the link below between time 4:26 and 4:36. I will be calculating the direction and the size of the force needed to make that hit happen. The average joe is 5' 6'' 160lbs. and the 6'5'' 360lbs. And also what the force is on him has he hits the ground.
• Kawala:

• Question: To test the roller coaster slows down when passing the second hill than passing the first hill, which obeys the principle of conservation of energy.
• Physical principle: Conservation of Energy. The car has initial kinetic energy when it starts so that it can go up the first hill. Then the potential energy turns to kinetic energy as the car goes down the hill. The further it goes, the more energy is transformed. The car has the maximum velocity at the bottom of the hill. As it goes up the second hill, the kinetic energy turns back into potential energy so that the car slows down. This also proves that the second hill of is designed to be lower than the first hill. The car cannot reach the same height as the first time because the energy is decreased due to the friction.
• How to approach: From the video I found, I can scale and use the logger pro to determine the velocity at different points. Also, the formula of the conservation of energy and kinematic equations can help to find some of the variables. Derivatives and Integrals might be necessary
• Quantities: Initial velocity, final velocity, the radius of the loop, the mass of the car, g

1. Kati: good idea. I like how you bring up the idea of whether to follow through or not. But which velocity are you gonna test? Is it the one when the player just hit the ball or the one when the ball is in the air?

Alex C: very creative idea. It's a good angle to approach. Can you give a little bit more that how do you do with the separation between the mass?

Alex K: It sounds like you have already had very clear method on this...Nice source and keep it up.

Mike: The first one is projectile motion. The second one sounds more interesting to me. I think there are certain difficulties to measure the force especiallly it's on yourself, but I think you should give a shot on this.

Toru: I like your idea, especially to analyze the rider's movement. I hope you can find a good approach when analyzing the force.

Brandon: You have some background info. already, nice work. Very good to involve both magnitude and direction!

2. First Cam i love your idea, but i feel as though you could go into a little more depth about it. Next Brandon i like your idea except for the part were the video gives you all the measurements and the calculated force of the hit, which is what you're looking for. If you could find force on a different hit of maybe a different sport i think that would be more useful than for you to basically check sports science's math. I think the rest of the ideas were pretty interesting and were raising good questions, and look forward to seeing the results.

3. Hey Kati this is a great idea. I've always wondered the same thing for golf. First off, that shot in the vid is a rip. I didn't know it was possible to hit a field hockey ball so fast. As far as the procedure goes, I have a few questions. Do you plan to take various shots yourself and put them on camera? If yes, how are you going to take a swing with "no follow-through". Does that mean the stick will hit the ground and stop just after contact with the ball? Or does that mean you will try to actually stop the stick yourself just after contact? (Probably some juicy non-constant acceleration there) Trying to actually stop at the ball seems difficult. Instead, maybe you could various shots with various follow-through's and come up with a function and go from there. This is a great idea, I'm very excited to see what you come up with.

4. Kati this is a comment on what alex said about stopping the stick. You could try setting up a bar or wall of sorts that won't allow the stick to go any farther than you want it to, allowing for you to get no followthrough.

5. Kati- Good idea, but hitting the ball with the same force consistently is difficult, so i think you should do multiple tests and average them

Mike- both ideas are interesting, but the kick seem difficult. Factors like balance, body angle, body position, will come into play when you kick, so it'll b hard keeping everything relatively consistent. Unlike Kati's swing, the kick will be complex, so there'll be a higher probability of errors. basically, the first one will be a safer choice.

6. Kawala: hopefully I will hit a good ball and it won't go in the air, but I will take the initial velocity.

Kane: yeah European's have crazy shots! Yeah I am going to video tape myself hitting the ball with the different follow throughs and average them. the swing with no follow through is basically just a slap shot and easier than it seems. Meaning that I will stop swinging the stick after I make contact with the ball.

Toru: I like your idea, how are you going to scale the app to the real world?

7. Great ideas! Instead of typing my comments I made a screencast of me scrolling through the post and making some comments on all the ideas. I hope it's helpful to you. Good luck!

http://screencast.com/t/J5VqclPT

8. Kati—you'll probably need a high speed camera to film your swing. I think Mr. G has one, so you're in luck.

Alex—I like Andy's idea to try to see if the mass is right for the game osmos—you could take frames of before and after the launch of a paritcle, and measure the sizes of the spheres sizes in something like tracker or geogebra. If you do it right, you might be able to tell whether the Osmos world has volume, or if it is only 2-D.

Mike—you might be able to measure the force of your kick by putting some foam padding on a force plate and then kicking it.

Toru—I like your idea a lot. Looks like if you use the height of each story as a scaling constant, you should be able to do this.

9. Alex ChristoffersonOctober 20, 2011 at 8:28 AM

Alex K - Waiting for someone to use this impact for a physics analysis, great job. The ideas are clear and i'm sure you will come up with some crazy forces but maybe try to see if you can find some way to relate the acceleration/time of impact to injury. See if what you predicted mirrored what happened.

Mike - I like the kicking idea but its a very large task. The air rifle one is much more calculation orientated which may require some calculus for air resistance but its an interesting idea. Maybe find some function for drop in height over distance (how they make sniper scopes right:) ? )

Toru- I love the idea and am jealous you are doing it before me. Try to also calculate things like after the elevator stops how high does he fly.

10. Mike- A possible variable you will have to watch out for when testing is possible wind speeds and the spin of the pellet. Seeing as pellets are round, they will be increasingly innacurate at longer ranges, so be sure to watch out for that.

11. Hi! I am an AP physics student from Ohio who is also starting a capstone project! I wanted to comment on Mike's post. As many of the other posts have expressed, I think that you might run into some obstacles in measuring the force applied by the kicks, but I definitely think that you will be able to figure a solution. One of my friends once used something called a force plate to do an experiment...I would look into that. I would also consider looking at the impulse of the kicks and what effect the values for impulse have in "the real world." I'm not sure, but I think that force plates actually measure impulse, so that might be a really good tool to use (if I remember my friend's experiment correctly). I agree that the other project might be more safe, but I think that you should go for the one with the kicks if it interests you; I think that you will be able to get more out of the project because it will be more challenging than the other one. Good luck with your project!

12. Thanks for the comment! Mike - we ordered two force plates, so they'll be in...sometime!

13. Hi, I'm also an AP Physics Student from Ohio. I'm really interested in all the roller coaster ideas that you guys came up with. I've had an app on my iPhone for a while called Coaster Physics and it might be great resource for anyone who is using roller coasters for their capstones. It lets you design and ride your own coaster and then see how speed, acceleration, kinetic and potential energy, and g force change as you ride along the track. It’s nice because it will do all the math for you and even graph everything. Also, I haven’t fully designed my own coaster, but the program has two really nice demos already installed. I think it’s an education app so it explains everything to you. I highly recommend it.

14. Hi, I am an AP Physics student in Ohio as well. Kati, I really like your idea about testing how fast a field hockey ball will go with or without follow through. I think you could add to it by also trying to hit the ball with a running start, and not? I don't actually play field hockey, so I wouldn't know, but that could add another aspect of the project, to make it more interesting. You could also try messing with the angle at which you hit it, which would also affect the velocity. This would be more difficult to have a consistent hit at certain angles, but I think it would be worth trying. Maybe also try it in different conditions? (Rain, wind, ect.), but this could get very difficult. Good luck with your project!

15. Hello! I'm also an AP Physics student in Ohio. Kati, I really like the idea of your project and I also agree with what my classmate said before me. Our field hockey team recently had a game on a field that was basically underwater =) so examining how much more force you have to apply to the ball or in what way you have to apply that force (ex. is lofting the ball or hitting it square on better?), depending on your conditions, could be interesting. You could also try hitting the ball on surfaces with different friction. Maybe there's a surface with so little friction that hitting the ball with no follow through is the same as hitting the ball with normal follow through on a regular field. Brandon, I like the idea of your project, too and I think you could take it even further by answering more questions that link physics and football like why some players start a play further back or how tackling and acceleration are related. Good luck with all of your projects!

16. Hi! I'm also an AP Physics student in Ohio. Brandon- good job on having something to work from (the video) so you can see what happens. I think it will help a lot when you are doing your project. Also its good that you know that you need an magnitude and direction. you could take it one step farther, though, by seeing how much force the average joe would need to hit the football player and make the football player do what the average joe did in the video. i realize it would be an unrealistic amount of force but just to show how hard it would be. and since you know the mass and once you find the force, you could find the acceleration with which the average joe hits the ground.

17. Hey, I'm also a part of the AP physics class in Ohio, and I just wanted to comment on Mike's second idea for a capstone project. I think the ideas of the kicks are really interesting, but it may enhance your project to look at their real world applications. If you're looking to win a fight by knocking someone out, you would need to know which parts of the body are most vulnerable and the amount of force needed to render them unconscious or unable to get back up to fight. You could compare the forces of each of your kicks with the parts of the body that are the most likely targets of each of these forces, and determine which is the best when trying to win a fight.

18. Hi! I am also an AP Physics student in Ohio, who is going to be completing a capstone project. Cam-It looks like you put a lot of thought into how you will find the displacement of the roller coaster. Are you going to graph position and acceleration with a computer program? Another thing to look at for this project may be energy to determine if energy is conserved throughout the whole ride. I'm not sure how you would check that one, but I think it would definitely be possible to calculate. Good luck on your project!!

19. Hi! I'm another AP Physics student from Ohio. It's funny that I can tell who posted some of these comments! Anyway- I had the same idea as one of the previous commenter. I think it would be interesting for Brandon to calculate the force that the average joe would need to launch the football player to the same height. Alex C, that game sounds pretty cool. I don't know whether you are considering the entire game or just the specific situation of shooting off particles. Depending on what you choose to do, it may be difficult to consider the changes in momentum that result from the cell merging with other cells. If you do that, you would have a lot of stuff with different angles and velocity components, but I guess you're going to have that either way. Make sure you choose your coordinate systems so you minimize the need to use components. Alex K, in the video, once the skateboarder was in the air, he turned and went down on his back. Maybe you could look into a way of landing that would decrease his risk of injury. Just some thoughts. Good luck with your projects!

20. Hello! I'm also an AP Physics student in Ohio! Alex K-I really like your idea! You might run into a bit of trouble though, considering all of the forces and angles in play - the fact that the ramp is curved means that he is not only changing speed but also the angle at which he is sliding, and the direction of the friction (as well as the normal force) is constantly changing. So if you were to calculate the acceleration for the skater to come to a stop by using the initial and final velocities, it would be assuming that the ramp is straight (and as you already said, the acceleration wouldn't be constant). Just something to take into account in case you haven't already considered it - and I might be totally off because you sound like you know what you're doing. Good luck!

21. Hi, I'm also an AP physics student from Ohio. Alex K, I am really intrigued by your project. I think you have thought a lot about some of the issues you are going to face and how to combat those issues. I wonder if you might want to look at change in momentum and impulse as another way to tackle this problem. Not that you necessarily need to make things more complicated, but I think what might be another interesting dimension to the problem would be to look at the role his helmet played in his survival. You'll know the acceleration so you can find the force and you could figure out how much force would have to be absorbed by his helmet for him to survive.
Kati, I'm not sure if you had already thought about it or not, but I think it's worth mentioning that I think you will need to do multiple trials. I think your plan to tackle the measurements is great but whenever humans are involved error is going to be an issue, and doing multiple trials will help to minimize the error.

22. Hi, I'm a middle-school English teach from Baltimore, Maryland. I just found you guys and really like physics. Just wanted to say, high-five, Kawala. Way to bring your A-game in the set-up here. However, You may want to re-phrase the question you're asking. It's not very clear what you're trying to accomplish with this project until you read every detail a couple times. (on a side note, it's pretty clear you didn't proof your post) You want your description to be straight and to the point. I'm also wondering how the mass of the riders will affect your project? Will you just pick a random weight? How exactly are you going about this? Also, I'm not sure if it was required of you, but it seems like every other student in the class whose project involved a video also posted a link. You may want to look into that.

23. Alex C.: Hi, I'm a physics student from Ohio. I'm not familiar with this particular game, but I have played something like it. I was wondering how you are going to determine the mass of the objects in the game. Assume uniform mass and measure the diameter perhaps? Is there a zoom feature? 'Cause that would be more precise. Also how are you going to determine the objects' accelerations?