Length of a wire from which the spring, much more length of the spring is twisted. To learn the extent of this wire, it is optional to spoil a spring, unwinding it. It is enough to perform calculation.
It is required to you
- - spring;
- - caliper;
- - vice;
- - protective gloves;
- - goggles;
- - calculator.
Instruction
1. Measure diameter of a spring in the compressed state by means of a caliper. Do not make at the same time considerable efforts for it, otherwise it will contract that will distort result of measurement towards reduction. It is the best of all to measure diameter in several places then to find an arithmetic average of results of measurement on the following formula: D=(D1+D2+D3+...+Dn)/n, where D - average diameter, mm, D1...Dn - results of measurements, mm, n - the number of measurements (dimensionless size).
2. Find length of a circle of one round on the following formula: l=πD where l is the circle length mm, π - number "пи", D - diameter of one round (mm). Actually the round has the form not of a circle, and an oval (because the wire possesses nonzero diameters, and each round even in the compressed state has diagonal longitudinal section), but lengthening at the expense of it is so insignificant that it can be neglected.
3. Count quantity of rounds of a spring (surely in completely unclenched state). Not to be mistaken, it is possible to use at calculation of rounds an elastic strip, for example, from flexible plastic. At each jumping from a round on a round she will publish distinct click. It is enough to count the number of these clicks and to add to them unit (the strip will come off the last round almost silently as will not hit against following).
4. Increase length of a circle of one round of a spring by number of rounds: L=lN, where L - length of a wire from which the spring is twisted, mm, l - length of a circle of one round, mm, N - quantity of rounds of a spring (dimensionless size).