Search for velocity in Topics


length affect velocity

Depending of length of a barrel can it change the velocity

Topic by Cheyannelovesham    |  last reply


Some acceleration problem? Answered

Lets say that a  ball of unknown mass is projected with and unknown force vertically upwards with a velocity of 40m/s. What's its deceleration??? Is it -9.81m/s2????? if so i need some explanations!

Question by ARJOON    |  last reply


How to measure Velocity/Acceleration of bicycle

I want to measure velocity or acceleration of a moving body(E.g: Car,bicycle,etc) without using a GPS module. Is it possible to calculate coordinate acceleration or velocity using an IMU.

Topic by Jonathanrjpereira    |  last reply


were do you get a good velocity measuring device? Answered

I need something to find the velocity from all of the guns i make does any where find one for relatively cheap?

Question by ilpug    |  last reply


Surface area drag?

Anyone know how to calculate how fast you will fall if you weigh 170 pounds and you have surface area a feet squared (if you wan't to calculate it I am thinking about 14 square feet

Question by jj.inc    |  last reply


Determining Distance With Math? Answered

Ok, I am only a freshman in high-school so I have know idea how to determine how high an object will travel at a given weight and size.  Does anybody know what this math is called and were I can learn it.

Question by jj.inc    |  last reply


What is the maximum velocity that could detect the optical sensor of a mouse?

I'm planning to do an anemometer passing a cilinder over the light and monitoring the velocity with software. Thanks in advance!

Question by aletoscano    |  last reply


How to calculate trajectory of projectile? Answered

How would I calculate the trajectory of a projectile with only the weight of the projectile, the velocity of the projectile at barrel, and angle of the barrel?  How did the artillery operators during WWII know how much powder to put or the angle of the barrel? Thanks for any help

Question by electronicz    |  last reply


How can I get a higher projectile velocity for my coilgun? Answered

I made a coilgun using 8 capacitors of 50V and 4700uf connected in parallel and powered by 4 batteries of 9V each. The coil is wound around a plastic tube over a length of 2 cm. However the projectile (an iron nail of 1 inch just popps out of the tube). How can I fire it at a higher velocity?   

Question by coilgunfreak    |  last reply


What is the "actual" impact velocities of two colliding objects? Answered

Is it relative to the observer, or one of the objects in the collision?  The reason I ask is that  Marilyn Vos Savant answered a question about this in her column and I think she did it an injustice by saying that: an object moving 50 MPH towards another object moving, say 40 MPH (in the exact opposite direction), that the force of the impact will be.....the same as if each had struck a stationary wall at each of those speeds.  I think she is assuming a "perspective" and not taking the relative postion of "observer" or participant into consideration making her answer, inaccurate depending on perspective.  (I've seen figures on the "relative" speed of a baseball leaving a bat) Any enlightenment on this would be appreciated.

Question by Goodhart    |  last reply


LSHV FAN

Has anyone attempted to make a large Low Speed High Velocity Warehouse Ceiling Fan?

Topic by darrinbaker    |  last reply


Suggestions for high pressure/velocity pumping of diluted tempera paint.

I've received the request to build a theatrical prop that should be able to shoot a diluted tempera paint 30- 50' from the gun. Any suggestions for where to begin looking for a pump capable of that kind of pressure or velocity to shoot a relatively narrow stream great distances? I don't think water pumps would be able to handle the extra viscosity of the diluted paint. This would not be aimed at anyone, but over a dance crowd. Amazingly, people pay money for this experience.  Anyone know what the guy with this green paint is using? Looks like a miniature fire hose. Many thanks for any suggestions! Instructables members are a talented and diverse bunch!  Everyone's answers have been very helpful. Through your suggestions and additional research we have determined that portable fire fighting pumps are the simplest method for moving a diluted paint solution great distances. The suggestions for using pressurized bursts of paint have also been helpful. Thanks everyone! 

Question by davidandora    |  last reply



speed of light?

I want to know the derivation of relative velocity formula used by Albert Einstein to prove that nothing can exceed the speed of light. Is there any simple derivation? please help

Question by deepakmurali    |  last reply


????If hot CO2 gas is passed through a solution of NaOH+H2O, is it possible to get Na2CO3? In which state will it be in? Answered

What would be the efficiency of the system if the gas has high velocity?

Question by coepian    |  last reply


Calculate DC motor specifications (torque power etc) for electric vehicle?

Dear Sir/Madam, I want to make an electric car like as shown in figure below., with a DC motor. assume no inclination, road is plain surface. please explain all calculation with formulas. Thanking in anticipation following is the basic known parameters: Total mass of car(including rider and everything) = 170kg initial velocity of car = 0 (still car stop) max velocity = 30 km per hour time to reach max velocity = 1 minute = 60 seconds radius of tyre = 8 inch please tell me how could i find the following parameters to find accurate DC motor for my car: how to calculate force needed by my car? how to calculate torque needed by my car? how to calculate speed RPM of a motor needed by my car? how to calculate power (watt) of motor needed by my car?

Question by amazn1    |  last reply


convert coilgun to railgun? Answered

Can I convert the coilgun into a railgun by replacing the firing tube with two rails? Should the current pass through the rails only for a moment (as in the coilgun)? Which can accelerate a projectile to a higher velocity? 

Question by coilgunfreak    |  last reply


LED display to an Audio Click? Visual click track aid for drummers required.

Hi Folks, I'm searching for some info on how to make a visual "Click track" aid. In one of my bands, we use a click track on some tracks and live on others. I use a single in ear monitor for the click track which s fine for most tracks, but for some, I need the click fairly loud and this cannot be good for the old lugs long-term. So, I want to make a small LED display or two that can react to an audio signal that is fed from the click track channel. I've seen many instructables that show how to make LED blink/flash etc to music, but my requirements are a little different (I think). The click at the beginning of each bar is higher in pitch and has a higher velocity compared to the other click in that bar, so for example; Playing in 4/4 time signature: click 1 - Velocity =100 - pitch C5 click 2 - Velocity =90 - pitch C4 click 3 - Velocity =90 - pitch C4 click 4 - Velocity =90 - pitch C4 If playing in another time signatures ie; 3/4 or 6/8, then I would also need to cater for this in the display Questions: 1. Does anyone know how I could devise a system that would light a Red led for beat 1 and then perhaps a white (or other colour) led for the rest of the beats, but in a sequential fashion? 1,2,3,4. 2. Is it possible to change which led flashes based on either pitch or velocity? I could even make the front of the led display show actual numbers over a perspex cover so at anytime, a quick glance will show me exactly where I am in the bar. So rather than coloured leds. So to recap, I'd like to be able to take an additional audio feed from the click track channel from a mixer, into this new "drummers visual click track aid" device and have it react to the clicktrack and display that in the form of beats per bar based on either pitch or velocity of the click track. I currently use a couple of wood block sounds for the click track because they are very clean and short. Many thanks for taking the time to read through my requests and if you're the kind of clever person who could make such a device, I'd be more than happy to pay you for your input and suggestions. Many thanks in advance and I look forward to hearing from you soon. Cheers Phill

Topic by CrashCourseMuso  


Calculate DC motor specifications (torque power etc) for electric vehicle

Dear Sir/Madam, I want to make an electric car like as shown in figure below., with a DC motor. assume no inclination, road is plain surface. please explain all calculation with formulas.THANK YOU following is the basic known parameters: Total mass of car(including rider and everything) = 250kg initial velocity of car = 0 (still car stop) max velocity = 60 km per hour time to reach max velocity = 1 minute = 60 seconds radius of tyre = 8 inch please tell me how could i find the following parameters to find accurate DC motor for my car: how to calculate force needed by my car? how to calculate torque needed by my car? how to calculate speed RPM of a motor needed by my car? how to calculate power (watt) of motor needed by my car? how to calculate battery needed by my car to travel 10 km in one charge?

Question by fawad_pappi    |  last reply


need help for coil gun

I want to make coil for coil gun.i have 21awg copper wire (0.7mm), 250v 10000 microfarad capacitor.How many layer for the best velocity ? 

Question by Rendydevara    |  last reply


what can i do with this old tablet screen?

I have salvaged an old lcd screen from a velocity micro cruz t301. it has a 60 pin ribbon cable connector. is there any way i can use this to connect it to rca cables?

Question by reggie88980    |  last reply


Container explodes after being shot with rifle? What mixture?

I saw this on tv. The guy was putting a mixture in a variety of objects, then backing away up to what a ppeared to be a hundred yards and shooting the container with a high velocity rifle. The explosion was large depending on how much was used. What was the mixture?

Question    |  last reply


Marshmellow guns

Hey, im new to instructables blah blah blah......yeh iv recently made a marshmellow gun but am really unsatisfied by the firing mechanism...blowing through a pipe is rather boring...so i was wondering if anyone could put an instructable on how to make a trigger mechanism or something which could extend its range, accuracy and velocity.....

Topic by scarecrow    |  last reply


Pulsejet engine turbulence model

Hello everyone i have conducted several pulsejet engine tests but today i tried to simulate a pulseejet engine in Ansys fluent 14.0 and here it is. This is a K-e model. The peak pressure at the instant of combustion was 2.5atm. The maximum velocity reached is about 800m/s and the peak temp was about 3000K.

Topic by ganuganu    |  last reply


How to calculate projectile distance of a trebuchet? Answered

Hi! After looking on the net for calculations to predict the distance of a projectile launched by a trebuchet, I've not found anything useful. There are many variables and each one can be changed to alter the projectile distance and velocity. I am looking for a simple way to calculate this without calculus.Thanks again.?

Question by 3.1415  


Calculating Drag When Firing Potato Launcher and Design Specifications

I'm interested in making a pneumatic potato launcher, I've found plenty information on that but I want to hit a target 255 meters away at an angle of 45 degrees. I calculated that I would need an initial velocity of approximately 50 m/s without wind resistance. The object being launched is an average sized potato under normal weather conditions. With wind resistance, what initial velocity will be required to hit the target? Please explain the process by which you came to the answer so that I may use the same method in future endeavors with different angles and distances. Also, just how much pressure would be required to launch a potato and achieve that speed, and to what specifications would the launcher need to be built i.e. how large the gas chamber will need to be, length of barrel, etc...

Topic by mike714    |  last reply


Terrestrial mass planet measured orbiting nearby red dwarf

From Science Magazine:A group of astronomers today announced the discovery of the least massive planet yet detected outside of our solar system. It is lightweight enough--between two and three times the mass of Earth--to almost certainly be rocky like Earth rather than a huge ball of gas. Although the planet orbits too close to its star to be habitable, a new analysis of one of its neighbors suggests a world with deep oceans.The observation of Gliese 581e, made with the usual radial-velocity residuals fit, is of a terrestrial-mass planet orbiting insanely close to a red dwarf star. Nevertheless, it marks a substantial improvement (a factor of three in mass) in the precision of the radial-velocity technique.Read the whole article (let me know if it's password protected) for details.Another news article (including a very nice diagram of the habitable zone as a function of the mass of Gliese 581) is available from Science News.

Topic by kelseymh    |  last reply


Physics question has me stumped

A large crate sits on a pickup truck which has coefficients of friction mu(s) =0.6 and mu(k) =0.4 . My question is how do I calculate the impact velocity if the truck accelerates (-8.0 m/s^2) and the crate slides forward 1.5 m to impact the back of the truck? Can anyone please walk me through this problem whenever you get the chance? Thank you. 

Topic by GThreep  


How to make an automatic shooting mechanism for a robot? Answered

It's a small robot and it needs to shoot marbles, its a combat robot, so it needs to shoot with high velocity and the shooting mechanism needs to be automatic. It should keep shooting marbles until the motor, or something else, stops any ideas on how to make this mechanism.Just like the one in the link below: http://www.youtube.com/watch?v=P8sBvgOQHX4

Question by Wisaam    |  last reply


preventing buildup of glutinous substance on duct walls?

During a manufacturing process, hot air flows through a duct carrying fine particles of a glutinous substance. With time, those particles stick to the walls of the duct and create a thick layer on them. This layer reduces the cross-section area of the duct, changing the velocity of the flow. To remove this layer, the flow has to be stopped. Any ideas of how to remove the layer without having to stop the flow? Or to prevent the buildup of the layer?

Question by khalednasr  


Arduino timer with photoresistors

For a science project i need to be able to measure the velocity of an object, to do this i planned to use arduino to measure the time between the object breaking a laser pointers beam onto a photoresistor and it breaking a second similar beam/photoresistor a set distance away. Alas ive had some trouble with the photoresistor side of things, can anyone describe how to properly implement a photoresistor? such as which ports i could connect it to and how to read when the beam would be broken.

Topic by shabaki    |  last reply


Can I Use an LED chaser circuit to make a large, sequenced coilgun? Answered

I saw an easy adjustable speed ten LED chaser circuit on the web and was wondering if I could use it to control relays in a coilgun that would be sequenced and therefore acheive higher velocities than others? Also, could I use a Wimshurst machine and homemade capacitors or leyden jars to power it, or do I have to use a ton of camera capacitors? Thanks!

Question by mad magoo    |  last reply


HOW CAN I FIND AIR GUN VELCOCITY FROM WIND SPEED? Answered

I need to know how i can make a extact scienctific calculaion of a air gun velocity based on wind speed, requirements so i can even know the laws and regulations of a exact air gun,bb gun,pellet gun,spring gun,and  airsoft guns #1 it must be extact as science #2 show your equation #3 include inperail units and metric OF BOTH  MUZZLE VECOLITY AND MUZZLE ENERGY while keeping it brief of one of only inperial,one only metric and one with a mixture of both or instead of number 3 you can include with just any unit as of that exact unit type for example kilograms and kilograms force,pounds force and foot pounds,kilogram force to joules be sure it inlcude units of joules,foot pounds,newtons, #4 include the wind speed and what the air gun velcoity of the bullet based on wieght and inlcude the amount per each amount of weight and per each amount of wind speed  I KNOW  IT IS  A BIG ASK HOWVER I NEED TO KNOW THE VELOCITY AND FIREPOWER THEN  I CAN EVEN CHECK THE LAWS

Question by 35Timmy    |  last reply


Turbocharger Compressor Characteristics.

Hi, I am working on building a micro jet engine, and I have to select between the following compressor wheels  http://www.ebay.com/itm/Turbo-charger-Compressor-Wheel-H1C-H1E-3599644-Ind-56-00mm-Exd-83-00mm/262249425295?_trksid=p2047675.c100623.m-1&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40130%26meid%3Da741d83f102946f8ab1a494b9f98692c%26pid%3D100623%26rk%3D4%26rkt%3D6%26sd%3D301844324395 or http://www.ebay.com/itm/HE351CW-HE431V-HX40W-HY35-Turbo-Turbocharger-Compressor-Wheel-4035879/111866311491?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D20131003132420%26meid%3D42565bcbcf264701aa897ff600931d8c%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D301844324395. However the seller does not seem to have any data regarding the wheels max RPM, slip factor, blade angle, and pressure gain at different RPM's ( probably a graph ). Is there any way I can get these piece of information about the wheels especially the first three. Most of the wheel parameters like the gas tangential velocity, radial velocity and the mass flow rate at the wheel's outlet need these values to calculate. Thanks for any help.

Question by fictionlife1659  


PD Control of Ball and Plate System (Stewart Platform) via Python and Arduino

Hi community,I'm prototyping a 6-DOF Stewart Platform, i.e. a parallel mechanism also known as hexapod, with an embedded resistive touchscreen on its top plate that captures the current position of a ball moving on it. Coordinates are stored by Arduino Due and sent via serial to a Python script which elaborates data, computes inverse kinematics and outputs the 6 servo angles (again via serial port) to Arduino that, finally, moves the arms. As you can notice, velocity is obtained by a one-side differentiator and here it comes my first question: how much should be the sampling step? It takes 124 microseconds for Arduino to execute both the "AnalogRead" functions, but coordinates are stored in Python at a different clock (order of one millisecond). I picked sampling step h (see attachment 2) equal to the computational time of the Python script, with decent results, but still I'm not convinced.My second issue regards tuning of the PD controller: I first described the system with a double-integrator transfer function (from assumptions and simplifications over ball&plate; control) but the obtained controller parameters were far from the optimal ones. Therefore a simplified model of motor dynamics was added to the transfer function and new PD constants were implemented: simulation and real behaviors are far from being identical (high delay, not null steady-state error, higher rise time, etc.); however, inside small ranges of error and with reduced velocity, the ball reaches an equilibrium basin. The third attachment depicts the final transfer function where:- K is K_m*K_ball*g (K_m:motor gain constant, K_ball: ball inertia, g: gravitational force)- T is tau_m: motor time constant;I set K_m and tau_m equals to torque (Kg*m) and velocity (rad/s) respectively, according to servomotors datasheet: is this the right choice?Thanks to everyone for even reading and for any upcoming help.

Topic by MatRob    |  last reply


Vortex tube should have a supersonic nozzle for efficiency; a simple drilled hole will not allow supersonic flow, right?

Scientific American had an article on supersonic nozzles in Amateur Scientist.  The nozzle needs to first narrow and then widen, so that maximum velocity is reached by the expanding air. The Hilsch tube seems to be very primitive because of details like the primitive nozzle.  Perhaps, the Hilsch tube was designed to have too much friction.  Perhaps, the tube was built to be sure it was inefficient and not very useful.  The tube can only violate the Second Law if it is built with a minimum of friction losses.

Question by R.Blakely    |  last reply


BB Gun, shot counter? Answered

I am planning on using an Arduino nano (clone or similar) but am struggling to figure out how I can use a proximity sensor or other method to count shots fired... Am not sure if I could use IR, as don't know if it will detect a break at the velocity the BB's will be getting fired at.. When I get something put together am planning on mounting a nokia 5110/3210 in the butt so is visible, maybe a laser range finder etc.. Any ideas would be much appreciated

Question by sparks_vfr    |  last reply


Good Paintball Mask?

I have a cheap jt paintball mask that came in a kit with a cheap pump gun I got a while ago.  The mask is just short of 1/8" thick and made of bendable plastic.  It offers protection from paintballs at 200fps but I am not sure about higher velocity guns.  It can only protect against up to 300 fps. So could I use it for battles with semi auto guns like viewloaders, tipman 98s and so on (beginner/intermediate guns)? or will I have to purchase a new one. Note: I have long since lost the manual for it.

Question by hunter1125  


Battery Hand Gun/cannon

Ok, so I'm planning to make this instructable, it shoots out batteries at incredible velocities. It's fairly dangerous. It involves the use of match powder. However, it has come to my concern that people might worry or even hate me for posting this instructable. So I'm going to ask users on this instuctable if yes or no, they want me to post it. Here's a picture of the damage it can make. The first picture shows the side where the battery first stuck into the 3/4 inch thick wood, the second shows the other side where the battery left. So, do you want me to post it?

Topic by IlluminatedAntichrist    |  last reply


Farewell - Jules Verne's fiery demise.

Europe's first Automated Transfer Vehicle (ATV) Jules Verne successfully completed its six-month ISS logistics mission today with its controlled destructive re-entry over a completely uninhabited area of the South Pacific. Following a final deorbit burn at 14:58 CEST which slowed its velocity by 70 m/s, the ATV entered the upper atmosphere at an altitude of 120 km at 15:31 CEST. It broke up at an altitude of 75 km with the remaining fragments falling into the Pacific some 12 minutes later. The words and pictures are from the ESA website, but I got first notice from SpaceWeather.

Topic by Kiteman    |  last reply


can i use the principle of Continuously Variable Transmission (CVT) to create a very efficient Flywheel?

Can i use the principle of Continuously Variable Transmission (CVT) to create a very efficient Flywheel? By this i mean, could i use the idea of a wheel with springs and weights that changes its moment of inertia at different angular velocities, to make a flywheel that would keep my small engine turning at top effieiency? This could be used in addition to, or to replace a standard flywheel. It would be for a custom built steam engine. All dimensions, everything custom, so anything is possible here. If you think this idea would or would not work, let me know! thanks

Question by MechEngineerMike    |  last reply


Can I use a fan to make a compressor? Answered

I have seen many centrifugal compressor designs on the net, I was wondering if a ducted fan can be used, duct's diameter at the intake of the air would be smaller, and after the air passes through the fan and is accelerated, the diameter of the duct would increase, I think this should lower the velocity of the air and as a result the pressure should increase, according to Bernouli's princinple, I am not asking like which one is efficient, the usual type of fans used in centrifugal compressors (don't know what they'r called) or this one, just asking if this would work and increase the pressure of the air.

Question by Wisaam    |  last reply


According to physics, does driving with a heavy load increase traction in winter?

Many Canadians enjoy adding weight to their vehicles over the winter to increase traction. How does it work? Since friction is force normal times mu, thus having a greater force normal means more friction. However since mu is usually so small, the increase in friction is negligible as compared to momentum. The momentum from added weight, mass times velocity would be dramatically increases, meaning longer distances to stop and easier fish tails around corners. Therefore less weight is more benficial. This is my logic, and I may be wrong. I don't know, thats why I'm asking...

Question by VentingIntrovert    |  last reply


Toy company hired to arm US military

A gun that fires variable speed bullets and which can be set to kill, wound or just inflict a bruise is being built by a US toy manufacturer. The weapon is based on technology used to propel toy rockets.Lund and Company Invention, a toy design studio based near Chicago, makes toy rockets that are powered by burning hydrogen obtained by electrolysing water. Now the company is being funded by the US army to adapt the technology to fire bullets instead.Bruce Lund, the company's CEO, says the gun works by mixing a liquid or gaseous fuel with air in a combustion chamber behind the bullet. This determines the explosive capability of the propellant and consequently the velocity of the bullet as it leaves the gun. "Projectile velocity varies from non-lethal at 10 metres, to lethal at 100 metres or more, as desired," says Lund.The existing VWS design is a .50 calibre (12.7 mm) rifle weapon, but Lund says the technology can be scaled to any size, "handgun to Howitzer".Experts warn that fatal mistakes could be made in stressful situations, with angry soldiers turning the dial up on mobs, or forgetting to turn it up when confronted by a situation that requires a lethal response.Me, I think we're more likely to find all the secret Star Trek fans crawling out of the military woodwork, cries of set weapons to "stun", Number One echoing across the training grounds...As an aside, Lund are the people behind Tickle Me Elmo as well, which makes images of armies of armed Elmos marching towards a mob; Hee hee hee, this will tickle, hee hee hee!Article in New Scientist

Topic by Kiteman    |  last reply


Anti-gravity Machine concept

This is a concept I came up with for an idea of an anti-gravity machine.  Let me just state for the record... I do not think this will actually work.  However, while I am quite certain this idea should not work... based upon my limited knowledge of science... it would seem like it could work.  Unfortunately I know I am never going to spend the thousands if not millions of dollars to build this concept to find out. The basic premise of the idea is the use of angular momentum to overcome the force of gravity.  Imagine if you will, a gyroscope spinning at such a high velocity that its outward force overcomes the downward force of gravity.  Naturally, one of the big obstacles is generating the speeds necessary to create the velocity such that angular momentum is greater than downward force. What I essentially propose is a spinning ring that is propelled in the same way as a maglev train.  Using Electromagnetic propulsion or EMP to accelerate a ring in a vacuum by the utilization of a flowing electrical current and magnetic fields may in theory generate the speeds necessary for the force to overcome gravity.  Unfortunately, the power to run such a vehicle and the weight to power ratio are significant obstacles. Two of these rings above one another I theorize can create tremendous propulsion if the angles of the rings were changed.  Using hydrolics to change the angle of alignment of these two rings may create incredible forward momentum.  Once more, such a vehicle would not be limited to operation within Earth's atmosphere unlike jet or other propulsion mechanisms.  In fact, it should operate at peak efficiency in a zero gravitational environment. This is all theory... and I'd love to know if it is indeed as crazy as it sounds.

Topic by DarkRubyMoon    |  last reply


A gun idea i cant work out

I been trying to make make this weapon but failed every time its the CBJ-MS made by Saab Bofors Dynamics here are the stats Weight 2.8 kg (empty) Length 363 / 565 mm Barrel length 200 mm Cartridge 6.5×25 CBJ-MS and 9×19mm Luger/Parabellum Rate of fire 700 rounds/min Muzzle velocity 2,723 ft/s (830 m/s) Effective range 150 m (6.5×25 CBJ-MS) Maximum range 400 m (6.5×25 CBJ-MS) Feed system 20, 30 or 100 rounds Sights Adjustable open sights this was copied from Wikipedia

Topic by headlessknight    |  last reply


Could a coil gun's projectile escape earth's gravity?

If there were a Coil Gun, that was built to go across the United States and Canada border, for 2000km in a horizontal line, that would end at the end of a 'tunnel,' the projectile should hit escape velocity 11.2km/s and be out of the earth's gravity's field?Coil gun launch cost964 MEGA watts 10 cents per kwh (wholesale) from a power station$9,640,000.00 per launchNASA Space Shuttle launch costhttp://www.nasa.gov/centers/kennedy/about/information/shuttle_faq.html#10Q. How much does it cost to launch a Space Shuttle? A. The average cost to launch a Space Shuttle is about $450 million per missionhttps://www.instructables.com/answers/Space-Elevator-or-Lateral-Coil-Gun/

Question by nfarrow    |  last reply


A way to calculate something about a ferromagnetic ball in a magnetic field? Answered

I've built something like this https://www.instructables.com/id/Mechanical-Rail-Accelerator---Non-electromagnet-%22r/ and now I am thinking of calculating the kinetic energy of a ball flying off the magnet if it was 'set off' by a ball at some velocity. I have a great lot of problems: 1 The ball is about the same size as the magnet, which makes it impossible to say it is 'infinitely small'. 2 It is near the pole, so the magnetic field is not even (not like inside a coil). 3 The ball is ferromagnetic, so the field is going to be even more disrupted. 4 There is no Physics teacher this week. Maybe (I hope) there is a formula of potential energy of something like my ball in a magnetic field? Any ideas? 

Question by gruffalo child    |  last reply


Jet Boat powered by High pressure Water Pump???

Hello Instructablers, I would love some input from some of the great minds in this community for slightly mad project I have been thinking about. In the spirit of "What Could Possibly Go Wrong" I am planning to try powering a small boat with an engine drive water pump. We recently got some new pumps in at work that will do up to 80m head (113 psi), or flows to about 750 litres per minute (I think that's about 164 gallons). Powered by 13HP Honda engine. It's a very impressive pump, but will it be able to power a boat? Here's my plan so far: Either obtain or build a small boat. Perhaps with a flat bottom. I will mount the pump as low and central as I can. Full of water the pump will weigh around 50-60kg. The suction hose would be connected to a tank flange that penetrates the hull at the deepest point. The discharge will penetrate the transom. Various nozzle sizes will be tried to find out the best compromise between flow and velocity. What do you think? Considering most of the jetboats I have seen have massive V8 engines in them, could my idea possibly work? Will it need to be an impossibly small boat? Will I need more than one pump? How many? What's more important; flow, pressure, velocity? Should I stick to oars? I have other pumps to choose from with greater flows if that makes a difference. Go here to see them:  http://www.pumpmaster.com.au/engine-drive-pumps.htm Here's silly video of the boys at Pumpmaster in Queensland trying out the new machine... http://youtu.be/zjYvENfr1cw

Topic by cammers    |  last reply


Figuring Out Acceleration on a Potato Gun

My newest craze is potato cannons. I built a simple potato cannon powered with hairspray. I didn't plan out ratios of chamber volume to barrel volume, but I must have guessed pretty well because the potatos go far. Really far. I shoot them in an empty bean field and they stay in the air for 10 seconds before hitting the ground at what I guess is 300 yards away. I want to measure it to be sure. I'm probably exaggerating the distance out of sheer amazement. But the potato goes really far. I got to thinking, though, that I could go beyond just shooting the potatoes, and actually turn this into something useful. If there was a way to determine the acceleration of the potato inside the barrel, that would be super cool. I've had a few ideas on this so far:The most complicated involves drilling holes on each side of the barrel. The holes would be every inch the entire length of the barrel. On one side led's would be installed and wired in parallel to remain on constantly. On the other side photoresistors would be installed and also wired in parallel with a microcontroller. When the potato traveled down the barrel it would block the light to some of the photoresistors and the microcontroller would get a readout. If there was a way to program this whole system and get a graph on a computer of the acceleration/time curve, that would be awesome!! Another way would yield a less accurate number. Shooting the cannon straight up and timing how long it takes the potato to hit the ground would give you the initial velocity. Vf = Vi + Gt, so: -2Vi = -9.81t . Once the initial velocity is known, if the time it takes for the potato to leave the barrel can be figured out, the acceleration could be figured out.Let me know what you think!Note: I will attach images as they come.

Topic by intoon    |  last reply