Any ideas/suggestions for building a catapult, where all energy must be contained in the system (no motors, electricity, radio controlled devices, CO2 cartridges, etc...) that can transport an egg, unbroken, a distance of 10 meters over a 2 meter wall?
134380
OOO, We did this project in IPC, except our was 20 meters -.-;;. You're ideal angle is 45 degrees. That usually gets you the farthest. It would be pretty smart to use elastic potential energy by using piece of bamboo or just a flexible stick (haha, flexible stick) or just a rubber band. Don't put anything on the egg. Our model was made with a giant rubber band that I found on the floor, and a little seat attached to the crossbow model. If your teacher is strict about a catapult model, your best bet would be to use the bamboo stick and research trebuchets.
186809
It doesn't say that the egg has to land on the concrete pavement!  Only that it is dropped 5 feet above a concrete pavement!  So I suppose you could have 5 feet of mattresses and lift the egg up about an inch or so and drop it down onto the mattresses, so that it was actually being dropped "5 feet above a concrete pavement without it breaking and without catching it"!\n\nBasically a play on words as this is:\n\nJUMP TABLES: Bet a bunch of friends that you can put three tables together, take your shoes and socks off and jump over them. They'll be anxious to bet that you can't. Take the bet money in hand then proceed to push the three tables together, take off your shoes and socks and jump over the shoes and socks. Then pick up your stuff and run as fast as you can!\n\nOr (with props the below):\n\nI would go with this: "The winning entry used "Rice Krispies" breakfast cereal in sandwich bags to enclose their egg."\n\n"Our technical support dept received the following question about dropping eggs:\n"I have been searching your web pages trying to find out how I can drop a regular raw egg off a roof without it breaking. Years ago I did this in a physics class, but cannot remember what I did. There is nothing in your web pages regarding this. My 7 yr. old grandson and I would like to do it. Could you help ?"\n\nNormally we can only answer questions related to our products, but we felt this question deserved a reply. To get a broad range of replies we asked the readers of our e-mail newsletter for help. \nSome of the answers we received\nGet an egg-eating snake, give it the egg and wait until the egg is about half way down the snake, then fit the snake with tail flights (cf a dart), then drop said snake plus egg from bridge etc.. The front of the snake will act as a crumple zone, thereby protecting the egg (makes a mess of the snake, but that is outside the parameters of the experiment) Then cut open the snake and remove the egg (snake already deceased, so this is no longer an ethical problem)\n\nIts really quite simple- can't imagine how he's forgotten that he dropped it while it was still inside the hen! Just make sure it's not a hen with clipped wings-specially if the roof is high...... \n\nTheory has it that, given sufficient height, aerodynamics will cause the egg to align itself to land on the blunter of the two ends. The egg is remarkably strong in this orientation. As long as it falls onto a reasonably forgiving surface, a lawn maybe, it won't break - sometimes!\nSafer bet is for Grandad to drop a hard boiled one and palm his stunned Grandson a raw one. \n\nI recently dropped an egg from a roof-top and was able to achieve a drop of some 15 metres without the egg breaking. How? The roof was 16 metres from the ground. It was that last metre that always did the damage.\n\nHold the egg carefully in your hands and jump off the roof. \nPut the egg in the middle of a 1 foot square styrene block. \nTake the roof off, sit it on the ground and roll the egg of the edge of the roof next to the ground. \nImmerse the egg in liquid nitrogen first \nFit the egg with a parachute. \n\nIt's really very simple, the clue is to spread all the force during the retardation phase (landing) on the COMPLETE surface of the egg. In this way, the resulting (vector) forces will be zero. In other words: The forces will "become a pressure" instead. And, since the egg may be compared to a pressure vessel (the surface is curved and can thus take really a lot of pressure before breaking) the egg will not break if you put it in strong bottle filled with water before dropping it!\n\nThis is the classical solution to the problem. I have never worked it out myself but it should work as long as the bottle itself is strong enough (do a test by dropping the bottle filled with just water before doing the test in front of an audience).\n\ncenter the egg in a nylon stocking. \nstretch
252831
Everyone must drop a egg from a height and not break the egg. All you can use is rubberbands and straws. So you cover the egg with straws (2 or 3 layers) and tie the ends with the rubberbands .
13593
I suppose, from your wording, that this is a variation on the egg drop test where the egg is put into a package first, and then dropped. I would guess that means a parachute is out of the question. \n\nThe list of exclusions seems a little illogical but one thing I don't see on the list is cotton, wool, yarn, or even plastic wool. A large enough quantity of cotton balls would absorb energy. \nWater? \nA partially filled balloon? \nYou could essentially replicate a 'foam' using attached balloons or plastic bags filled with air. \nHow about a net made of elastic fiber? The elasticity, weave of the net, and the angle of the net's parabolic form would all be variable factors.
465513
georgex is exactly correct about how aerodynamics come into play in this situation.\n\nI would just add the observation that wind resistance is not a significant issue in the acceleration of the missile (and the acceleration of the various parts of the catapult). The acceleration occurs over a very short period of time, and the main resistance to accelerating the missile is the MASS that needs to be accelerated, not the wind resistance.\n\nOnce the missile has been released, it is travelling very fast (which means that the wind resistance will be very significant), and it will be travelling for a considerable period of time (which means that the wind resistance will be slowing it down for a relatively long time and a long distance). So wind resistance is much more important during this phase.\n\nIf you want to make your question more specific, you might get more specific responses.
172885
I like the jello answer. I would use a bunch of cotton, but also find a way to suspend your egg in a number of rubber bands. They need to be tight enough so they don't stretch too far, but loose enough so they move on impact. In combination, the cotton and the rubber bands should protect your egg.
190054
in all probability i think: yesh, it would. i can find no flaw in your logic. but in power stations i suppose it is better to use big cats. an improvement on power can supposedly be obtained to release the feline over water to increase the levitation efficiency.
265851
Find yourself a box of the correct dimensions.\n\nWrap your egg in bubble wrap--the kind with the bubbles that are about as big as a quarter.  Wrap it in as much as you can use without going over the weight limit.  The egg should be in the center of the bubble wrap.\n\nThe bubblewrap should prevent the egg from breaking.  The key is to get the egg in the center so it has equal bubblewrap around it.\n\nIf you can find a styrafoam box that is 7cm x 7cm x 7cm, that would be the best as it would easily meet your 400cc requirement and no side longer than 20cm!  Plus, styrafoam will absorb shock!
633035
The simple answer is to have a mechanism for absorbing the impact of the fall. What to build depends on what materials you are restricted to.\n\nThere are several ways to go about it. Design a super-structure (the outside part) that crumples when hit. Suspending the egg is also a great idea (as was already suggested) If you can't or don't want to use a sock or stocking, using some kind of thick substance like gelatin would work well. Parachutes also work very nicely, I've seen some cool ones that worked like helicopters, spinning to slow down the descent. If you want a better answer I suggest posting whether you are restricted to certain materials.
488474
You can make a ball bearing launcher:\nhttp://my.execpc.com/~rhoadley/maglnch.htm\n\nYou can make your own levitating MagLev train:\nhttp://my.execpc.com/~rhoadley/magtrain.htm\n\nOther info is available here:\nhttp://www.kn.sbc.com/wired/fil/pages/listmagnetsan1.html
124327
It's been forever since I've done it, so I can't give you an actual schematic (try a search engine for that.) I will give you some tips from my science olympiad glory days, however. I assume you're trying to lift the most weight?\n\nMake your sails out of the lightest material possible and with as little re-enforcement as you can get away with it. That way the energy going into turning the sails is minimized and they can rotate faster (and hence do more work.) Depending on size, posterboard or even paper with a balsawood backing usually works well.\n\nDo you know what will be turning the windmill? If it's a fan, try to find one like it and test against that. If you're using natural windpower, this will be harder to do. Only re-enforce the sails enough so they won't get torn apart.\n\nAs far as the string lifting the weights goes, friction is GOOD. You don't want it slipping and costing you energy and time, if time is an element. In all the other elements, friction is BAD. Break out the ssandpaper if necessary.\n\nAll of this is probably common sense, but I hope I did some good. Best of luck.
208034
HI MAWBY --\n\nI ANSWERED THIS YESTERDAY IN SOME DETAIL.\n\nPLEASE GO TO THE SITE AND QUESTION BELOW.\n\nITS IN THE AILERONS, TABS, AND ELEVATORS.
589839
Hope this helps you out , you might want to download a program called webferrett it will find just about anything \n\nwww.redstoneprojects.com/trebuchetstore/build_a_catapult.html
241816
i actually did this in highschool, find a small square box, inside the box you need to put foam rubber(like you would find inside a couch cushion") any craft store will have numerous varieties of this.....line the box with it leaving a space twice the size of the egg. wrap the egg tightly with cotton batting (also available at your local craft store)....make sure that the egg CANNOT MOVE! The foam will absorb the force of impact and the egg should not break. finally, decorate your box as you see fit to make it sale worthy............................good luck!
141471
An egg is pretty aerodynamic, so we can neglect friction. Thus, a falling object satisfies the equation\n\ns(t) = -0.5*g*t^2+v0*t+s0\n\nwhere g is 9.82 m/s^2, v0 is the start velocity (in this case, 0) and s0 is the start height (in this case, 3 metres).\n\nSo, letting s(t)=0 and solving for t, we get\n\n0 = -0.5*g*t^2 + 3\n\nt = sqrt(6/g) = 0.78 seconds.
81171
Attach a falcon to the prototype.. Think it will fly high! :-)
58510
>>>Can gravity be used as a means of propultion?\n\nIt can and it is. Have you ever seen a flying squirrel? Or a petrel diving on a fish? They are using gravity as a means of propulsion. \n\n>>>>>For instance if it is possible to create a device which "bounces" off of gravity. \n\nYou can’t ‘bounce off’ gravity. Gravity is an attractive force, not a repulsive. \n\nThe suggestion is nonsense. You might just as well ask whether you can stand at the top of a well and use the hole to fall up to the sky. \n\nOr maybe ask whether you can use the negative speed of a stationary vehicle to get back where you came from. \n\nIt makes no sense in a  ‘sunbeams trapped in a jar as a nightlight’ kind of way.\n\n\n>>>>>somebody said "gravity is an attractive force"\n>>>>> therefore it is a force... so what about the concept >>>>> of anti-gravity?\n\nThat's way outside my ability to comment on. Anti-gravity depends on the production of anti-gravitons. We don't even know if gravity is caused by gravitons yet, we've never seen one. We've ceratinly never been able toproduce an anti graviton. It's all science fiction stuff. I gather it's possible in theory if certain theories are correct, but in practice.....