how did they measure speed accurately before electronics?
110069
The simple answer: Mechanically.\n\nDepending on the sport, and the timing requirements, all events were timed with the mechnical stop watch, or an instrument similar to the stop watch.  Either a live person actually started and stopped the timer. Or in some cases, they did have what could be considered a type of laser light mechanism that stopped the timer device.\n\nNot sure how much detail you want. But hope that helps.
1005598
I believe it's a.\n\nHere is what i found:  \nDoppler radar uses the Doppler effect to measure the relative velocity information from a radar system. The Doppler effect shifts the frequency of the radar reflection based on the relative velocity (speed) of the "target", allowing for the direct and highly accurate measurement of speed.
966205
(a) too trivial to answer\n(b) Take the average speed times the number of seconds over which it had that average speed.
202588
You can build this Gadget using two camera, and the base of stereo-photography; where you can calculate / triagulate the distance in the same way that you can see depth/distance because you have two eyes.  \n\nNew police speed detectors in developemnt use this technique. (it will be undetectable by radar detectors) They use will two cameras, calculate the distance of an oncoming car, wait about 1 second, determine the disance again, then calculate the speed of the car. (Then they will write youa ticket !)\n\nBasically, it is simple geometry. Using two cameras that are a fixed known distance apart, you can then determine the angles by seeing how many degrees you have to adjust the two images (from both cameras) to make the edges of the object in the image overlap.\n\nIn Euclidean geometry, the sum of the internal angles α + β + γ is equal to two right angles (180° or π radians). This allows determination of the third angle of any triangle as soon as two angles are known.\n\nMultiply the distance between the two cameras times tangent of the angle, to determine the distance to the object. Wait 1 second, do it again, and you will know the distance traveled by the object by subtracting the first distance fron the second, then take the abslute value of that number (in case it is traveling away from you, to avoid getting a negative number for your answer).\n\nGood luck !
263422
Distance=rate*time\n\nJust plug in what you know and solve for what you're missing.
281745
Navigation with trig uses the basic principals of the patagorean theorem (a squared + b squared = c squared), sin (pronounced sine), cosin (pronounced co-sine), and tan (tangent).  If you remember the helpful hint SOH CAH TOA (pronounced so-cah-toe-uh) it will help you to remember sin = opposite over hypotenuse, cosin = adjacent over hypotenuse, and tan = opposite over adjacent.  These refer to the sides of a traingle.  Draw a right trinagle (that is a traingle with a right angle in it).  To find any one of the angles, you use what I described above (if you know the length of the sides).  You can mix the equations up and solve for any part of it that is unknown if you know the other two.  Now, back to your question...  A navigator will usually have a chart (map) with a scale on it (measurement on the paper).  With this he / she can tell the distance between any two points, thus giving the length of the side of a traingle.  If they do this from a couple of different points, it is called "triangulation".  Now they have the "triangle", they use the stuff above to figure out the angles, distances or whatever.  Finally, they use a formula of distance = rate x time (D=RT) and variations of it (T=D/R, and R=D/T).  Let's say the navigator want to know how long it will take to get from point A to point B.  They use what I've described above to measure the distance (D), and they know how fast they are traveling (with a speedometer or airspeed indicator, etc).  Now they can use T=D/R to figure out how long it will take to get there.  In "old" times, the accuracy of charts and maps was not quite up to par, so they used the "stars" as thier maps.  these were "known" quantities, with specific angles to the horiozon (which remained fixed).  The device they used was called a "sextant".  This gave them a reading of the angle.  They would also used an hourglass for time, and a specially-made board with a rope with knots in it.  As they let out the board and it hit the water, they would "time" how many knots passed through thier fingers.  This gave them "rate" (or speed).  Using what I described above, they could figure out the rest.  Hope this helped.
746498
As you go back in time, the electrical measurements were not always measured with a digital display.\n\nWhen you are using an analog device - the measurement or reading was shown by a needle or indicator - which is designed with an electro-mechanical principle - based upon electrical deflection in a magnetic field and has been calibrated with a spring loaded element. The springs in pressure gages as well as electrical devices are not always perfectly linear and have a chance to be sticky at the low end ( that is why they always ask you to tap these devices lightly before taking a reading ). Therefore to reduce this error the measurements in analog meters were moved to 4-20 mA, 10-50mA, 1-5 V etc.\n\nHowever with a digital readout device there is no such need, but the continuity wherever it exists is based on the analog measrement history.\n\nThe same is applicable to the pneumatic devices where the signals are of very low pressure vaues such as 3 -15 or 3 -27 psig etc.
790422
If you have a GPS or access to a GPS that would be the best most accurate way to measure your distance, speed and route. And they are extremely accurate.\nThen you can DL the information from the GPS to your mapping software that comes with the GPS and you can get a overall visual of your route.\nNot to mention they are coming way down in price.
212447
it's like the speedometer of a vehicle. the higher the reading the faster it is...
620893
The best way to work this out would be to plot a speed time graph for the information.\n\nOr you could express it as a simultaneous equation.
676092
Uses the Doppler effect to detect frequency shifts in the transmitted pulse caused by the radial velocity of detected targets.  The echos is processed through a series of RF filters &, based on the amount of frequency shift & angle of approach, the radar can then determine the true target velocity.\n\nMostly used in weather apps.\n\nPS. the speed of light is normally rounded to 3*10^8 meters/sec or 300,000,000 m/s.  Also Doppler is a guy's name.  (Christian Johann Doppler 1803-1853 Austrian physicist)
832862
G.P.S.  Before gps they used a compass.
1076490
Do you measure the speed? \nIn that case a feed back loop should be easy to make with Labview:\nmeasure the speed, and *slowly* change the current according to the difference with the requested value.  \n\nYou can measure the speed by counting light pulses from a light seen through  a hole mounted on the motor (or the object your driving with the motor).
472649
"Accurately" is a difficult term; you don't state how accurately.  However, when I was working on electric vehicles, we had the same problem, and got a special sort of GPS (Global Positioning Satellite) Receiver, called a survey logger.  This, now that SA is ancient history, should be accurate to a few meters, for position, if mounted correctly.  It will take a log of the position, at rates of up to 1Hz, if you get the right kit, and then taking the derivative of the position can give you speed, a second derivative gives acceleration.\n\nALTERNATELY if the acceleration is high (as in a crash), then you need to mount an accelerometer, or a set of tri-axis accelerometers.  The signal from these can often be logged to a laptop computer.\n\nNot a definitive answer; hope this points you in the right direction.
501038
you just have to divide the speed change of 15km/hr by 5 seconds.\nthat's 3 km/hr/every second
693415
You take the avaerage of the instantaneous velocity over an interval of time.\n\ntake say five instantaneous velocity measurements over about 40 seconds. then take the average of these five measurements to get a linear velocity. to make your answer more accurate just take more than 5 mearsurements and average them in the same matter.
448583
what do you mean?\nhow to calculate their speed or wat?