What is Meter: Definition and 309 Discussions

The metre (Commonwealth spelling) or meter (American spelling; see spelling differences) (from the French unit mètre, from the Greek noun μέτρον, "measure", and cognate with Sanskrit mita, meaning "measured") is the base unit of length in the International System of Units (SI). The SI unit symbol is m.
The metre is currently defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.
The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately 40000 km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length.

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  1. V

    Digital Capacitance meter using microcontrollers

    Hey friends, I am trying to make a digital capacitance meter by using a HSC08 microcontroller chip (MC9S08QG8). Unfortunately this is one of those courses where one doesn't know anything because of lack of pre-requisites. Anyhow (enough complaining) what I have been trying to do is the...
  2. M

    What would be the effect on the results if the venturi meter was not horizontal and w

    What would be the effect on the results if the venturi meter was not horizontal and why? This is research i must complete before I carryout my experiment and lab report?? Help Plz
  3. A

    Dynamometer Principle & Operation | Load Testing Accuracy

    Dear all The eddy current dynamometers are used to load testing of motors and gearboxes.Can anybody explain the principle and operation of dynamometers and load testing accuracy.? Thanking u Prakash
  4. C

    What is the moment of inertia of the particle at the end of the meter stick?

    Moment of Inertia A particle of mass 0.400 kg is attached to the 100-cm mark of a meter stick of mass 0.100 kg. The meter stick rotates on a horizontal, frictionless table with an angular speed of 4.00 rad/s. Calculate the angular momentum of the system when the stick is pivoted about an axis...
  5. L

    How Does a Venturi Meter Calculate Fluid Speed Using Bernoulli's Equation?

    1. Find , the speed of the fluid in the left end of the main pipe. Express your answer in terms of h_1, h_2 , g , A_1, A_2. 2. Bernoulli and continuity equations 3. p_1 = rho*gh_1 p_2 = rho*gh_2 p_2 = p_1 + 0.5rho*v_1^2 + 0.5rho*(A_1/A_2)^2 * v_1^2 I know those are...
  6. Z

    Suggested ICs for Outdoor Speaker Sound Level Meter

    what ICs can u suggest to be used in my sound level meter for outdoor speakers in order to have an accurate measurements. power amplifier to be used will be 50, 70, 100 watts power out put.
  7. P

    Torque of suspended meter stick

    Homework Statement A uniform 1.0-N meter stick is suspended horizontally by vertical strings attached at each end. A2.0-N weight is suspended from the 10-cm position on the stick, another 2.0-N weight is suspendedfrom the 50 cm position, and a 3.0-N weight is suspended from the 60 cm position...
  8. K

    Period of Oscillation of a Meter Stick

    Homework Statement Measure the period of oscillation of a meter stick suspended at one end for small amplitudes. Does T = 2*sqrt(2I/mgL) when I is the rotational inertia about one end? Derive this relation. Homework Equations I = rotational inertia m = mass g = gravitational...
  9. I

    How does my energy saving meter work?

    Hello! I've just brought an Energy Saving meter, to see how much electricity my household uses and I'm kinda curious as to how it actually works. It's an efergy standard meter. It has a clip that you place on the wire leaving your household meter, which seems to have a magnet in it. I...
  10. H

    Falling meter stick on a frictionless surface

    Homework Statement The question I'm working on says "A special, frictionless, thin meter stick is initially standing vertically on the floor. If the meter stick falls over, with what angular velocity will it hit the floor?" Homework Equations v_rot=rw, I=1/12mL^2, KE=1/2Iw^2 The...
  11. DaveC426913

    Understanding How My 'Average Mileage' Meter Works

    How does my 'average mileage' meter work? When I reset it, it starts averaging right away, so the first few miles have a big impact on the value. But after a hundred miles, each mile (including those first few) has a tiny impact (1/100th), right? If my driving habits change, these changes...
  12. S

    Finding Current in a Circuit (to get current going through an amp meter)

    Homework Statement http://dl.getdropbox.com/u/119186/Picture%20122.png Homework Equations Voltage Drop = -I*R I1=I2+I3 Reqiv= 1/R1 + 1/R2 etc. The Attempt at a Solution I really have no idea how to approach this. A1 and A2 won't have the same current will they? I tried getting an...
  13. F

    Determining speed of an object with only a meter stick?

    A child wishes to determine the speed a slingshot imparts to a rock. How can this be done using only a meter stick, a rock, and the slingshot? This question seems impossible to me, since you would HAVE to take time into account at some point, in some way, to figure out speed, right? So is...
  14. Pengwuino

    Accuracy of a meter stick

    I was grading my labs and in this lab, we used a meter stick and a wooden protractor. A group finally wrote in their write up that they believed the error was due to the inaccurate nature of the equipment. This begs the question, what sort of tolerances do you see in the manufacture a typical...
  15. A

    How does this Dark Meter work?

    How does this "Dark Meter" work? In our physics lab we used photoresistors to make a simple circuit that is light activated. It was essentially a battery hooked up to a photoresistor which was in series with an ammeter to measure the current. When the photoresistor is blocked there is low...
  16. D

    Unit Of Measure For My Electricity Meter

    So I was trying to figure out how much power items at my house use. I have a standard looking power meter outside with the dial http://en.wikipedia.org/wiki/File:Electrical_meter.jpg" . I am trying to figure out though what unit the meter uses. My first instinct was watt hour, but I can't get...
  17. S

    How Does a Torque Meter Measure Engine Torque and RPM?

    I am going to measure the torque output of an diesel engine @ various RPM to understand the resistance of the gearbox connected. I wonder is there any guides for Torque meter DIY and the basic principle of a torque meter that can measure RPM + torque. Thanks in advence.
  18. C

    Hakk effect gauss meter practice

    Hi everybody... I am studying the theory hall sensor for magnetic particle testing...It is a usually techinque non destructive for aeronautic application..In one paper i have read "the hall sensor respose is proportional to the sine of the angle between B and the plane of the hall sensor"..The...
  19. L

    How does a dose rate meter determine dose with only a GM tool?

    I'm talking about one of these: http://www.eldan.biz/emall/shops/1903/45983-tb-Automess-dose%20rate%20meters.jpg The use a Geiger-Muller gas chamber which can only detect when A UNIT of gamma or beta radiation (or alpha if you have a really tiny window) goes through, but it says nothing...
  20. Saladsamurai

    Venturi Meter Finding Pressure Difference

    Homework Statement I guess I am having a hard time seeing what that manometer is doing. I assume that as fluid moves in at 1 it causes a displacement of the manometer fluid by some distance h. Now, are we assuming that the pressure is uniform throughout the diameter of the pipe...
  21. B

    Converting Fish/Liter to Fish/Square Meter

    Hi, I ma having problem, can anyone help me converting ""individual/liter to individual/square meter" for example 20 fish/L = ?? fish /m2
  22. G

    Venturi Meter with Bernoulli's

    Homework Statement Water flows through a venturi meter, with an inlet diameter of 25cm and a throat diameter of 15cm. The pressure difference is measured using a manometer, which displaces the mercury by 12mm on the throat side. Homework Equations Bernoulli's Mass continuity P=rho.g.h...
  23. L

    How do these machines work (parking meter, etc )

    Hi guys ,, how are you all ?? my teacher had us to make a report about parking meter and the coins we are using for it ,, the new issued ones doesn't work with the parking meters ,, so i have a question ... how does parking meters , Pepsi machines and other machines that you have to...
  24. N

    Good fluke meter runs around $300

    well I am going into the electrical field and was wondering if the "hype" on multimeters is true. i am currently in the automotive field electrical class and my teacher only recommends a fluke meter. he is so certain its the best to go with he swears on it. i don't know much about the quality...
  25. R

    How long is the image of the meter stick?

    Homework Statement The figure shows a meter stick held lengthwise along the optical axis of a concave mirror. (Intro 1 figure) - figure attached How long is the image of the meter stick? Homework Equations 1/f = 1/do + 1/di [b]3. The Attempt at a Solution [/b 1/di = 1/f -...
  26. B

    Redefining the meter, kilogram, etc.

    Homework Statement This isn't homework, it's just something that I've been thinking about, but I thought that this was the best forum to ask this. The meter was first attempted to be defined as 1/10 millionth of the distance from the North Pole to the Equator through Paris. This seems...
  27. K

    Bernoulli's Equation and venturi meter

    Homework Statement A venturi meter is a device for measuring the speed of a fluid within a pipe. The drawing shows a gas flowing at a speed v2 through a horizontal section of pipe whose cross-sectional area A2 = 0.0600 m2. The gas has a density of ρ = 1.60 kg/m3. The Venturi meter has a...
  28. S

    Connecting HP 4140B pA Meter for VI Curve Measurement

    Hi, I'm trying to make connections with a pA meter / V source. It is a HP 4140B. Let's just say I'm going to try to find the VI curve for a resistor. The voltage source is coax out. I think I know what connections to make here but could someone help me anyway? The current in is via...
  29. H

    How many square centimeters is a square meter?

    How many square centimeters is a square meter, and how many square meters a square kilometer? thanks
  30. S

    Calculating Mass of 1 Cubic Meter of Water in Kilograms

    Homework Statement Assuming that each cubic centimeter of water has a mass of exactly 1.00 g, find the mass of one cubic meter of water in kilograms. Homework Equations well i just changed everything from grams to kilograms and cm to m The Attempt at a Solution Well if there is 1g...
  31. R

    Finding turns per meter in a solenoid

    Homework Statement The magnetic field produced by the solenoid in a magnetic resonance imaging (MRI) system designed for measurements on whole human bodies has a field strength of 4.0 T, and the current in the solenoid is 300 A. What is the number of turns per meter of length of the...
  32. J

    Measuring laser output with Lux meter

    Hiya, Question 1: (Main question) I bought a lux meter while understanding very little about how light is measured. I'm hoping to measure the output of a laser in mW. I assume it's possible to do this at least to an accuracy of about 10-20% which is all I need? If so, please could someone help...
  33. Z

    Stargazing Discover the Capabilities of 25+ Meter Telescopes Beyond Engineering Projects

    Other than an engineering project, what could we look at with a 25 m+ telescopes? http://en.wikipedia.org/wiki/Thirty_Meter_Telesco"
  34. T

    How to convert m meter into recoils

    Hi as the single photon recoil is p=hbar k and k=2pi/lambda
  35. A

    Calculate Water Speed in Venturi Meter

    Venturi meter help! Homework Statement A venturi meter is measuring the flow of water; it has a main diameter of 3.0 cm tapering down to a throat diameter of 1.0 cm. If the pressure difference is measured to be 16 mmHg, what is the speed of the water entering the venturi throat...
  36. V

    Hey guys help with Venturi Meter question

    A venturi meter with a 75 mm diameter throat is installed in a horizontal 150 mm diameter pipeline. The pressure at entry to the meter is 70 kN/m2 gauge and the pressure at the meter throat must not fall below 25 kN/m2 absolute. Calculate the maximum flow for which the meter may be used, given...
  37. snoopies622

    Length of Meter Stick Near Event Horizon of Black Hole

    I am not clear on how |g_{rr}| \neq 1 in the Schwarzschild solution manifests itself. If I approach the event horizon of a black hole while holding a meter stick "vertically", that is, with d\theta =0 and d\phi =0 between its endpoints, will it appear to someone far away (r \gg r_{s}) that its...
  38. Ed Aboud

    How do you convert watts per meter squared to decibels?

    Hi. How do you convert watts per metre squared to decibels? I know you use logs but can't seems to work it out. Thanks for any help.
  39. A

    Understanding Ground Potential: My Experience with a Volt Meter

    Hi everyone, I just bought a volt meter today to play around. To my understanding about electricity and all, I've always been taught that potentials have references. We always reference ground as zero potential. I put the volt pins between a small battery and it reads about 1.6 volts, so I...
  40. L

    What are the meter readings in the circuit?

    Homework Statement http://img372.imageshack.us/img372/8240/1005200803ki4.png What are the meter readings in the circuit on the top? Homework Equations V = IR The Attempt at a Solution I = \frac{V}{R} A_2 = \frac{12}{\frac{20}{75}} = 45A A_3 = \frac{12}{\frac{30}{75}} = 30A...
  41. L

    Calculate the resistance per meter

    Homework Statement Calculate the resistance per meter at room temperature of a constant wire if diameter 1.25mm. The resistivity of constant a at room temperature is 5x10^-7\Omega{m} Homework Equations I'm not sure, but I think this is the right formula: R = \frac{Pl}{A} The...
  42. L

    Rotational Dynamics of a meter stick

    Homework Statement A meter stick of mass .44 kg rotates, in the horizontal plane, about a vertical axis passing thru the 30 cm mark. What is the moment of inertia of the stick? Treat it as a long uniform rod. Homework Equations I=1/2M(R^2) The Attempt at a Solution...
  43. M

    Electrical energy meter errors

    A three phase and three wire energy meter has installed in a medium voltage network with a lot of third harmonic current and unbalanced load (approximately %10). As you know, any distortion in sine wave and deviation of rated frequency in AC electrical system may be cause the increasing of...
  44. T

    Engineering 101: Understanding One Meter (1 m) & Weight Measurements

    To all the engineers or the enginnering students out there. How do you give the definition to one meter (1 m)? More: How much do you weight in Newton, slug, and pound-force (lb_f)?
  45. C

    Can Using a Single 220v Line in My Bedroom Affect My Electric Meter Reading?

    In my bedroom I use a single 220v line and made an electrical outlet while the second line is connected to the water facet which is obviously the ground. the result is a 110v power source. I use this to power my lamp shades and other bedroom lighting. so my question is, since iam only using a...
  46. T

    Calculating the Reading on Newton Meter with 3 Kg Masses

    Homework Statement A pulley system is hanging from a Newton meter as shown below. If we assume that gravitational acceleration is 10 m/s^{2}, what will the reading be on the Newton meter as the masses accelerate? a) 3 Kg b) 13 N c) 27 N d) 30 N...
  47. M

    Calculating Pressure and Velocity in a Venturi Meter Setup

    Homework Statement A pair of vertical, open-ended glass tubes inserted into a horizontal pipe are often used together to measure flow velocity in the pipe, a configuration called a Venturi meter. Consider such an arrangement with a horizontal pipe carrying fluid of density p.The fluid rises to...
  48. P

    Fluid Mechanics- Venturi Meter Problem

    Homework Statement Air flows through a venturimeter as shown below (rudimentary sketch of a typical venturi meter pictured). Neglecting frictional effects, obtain an expression for the volume flow rate in terms of pressures P1, Pthroat and areas A1, At at the inlet and the throat...
  49. G

    How Do You Build a kWh Meter for a School Robotics Project?

    How to build a kwh meter?? I would like to seek some information on how to build a kwh meter to check the power consumption for my school robotic project? Please tell me what are the components that are required to build one? Thank you. Regards, Gyro
  50. B

    Help Me Measure Capacitance with ASL MODEL 1055

    Not sure where I was supposed to post this; but I think here it will hopefully get the attention of someone who can help me. I am working on a project where I have to measure capacitance very accurately. I have been given a: ASL MODEL 1055 MANUAL DISPLACEMENT METER. But I've been, along with...
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