It is now required to estimate the total length of a coil of bare wire (3 types) without pulling apart the coil of copper wire but cutting off a section of copper wire

It is now required to estimate the total length of a coil of bare wire (3 types) without pulling apart the coil of copper wire but cutting off a section of copper wire

1. Weight measurement method, measuring a section of weight, length, total weight of side, length
2. The method of measuring resistance is the same as above, but it is changed to measuring resistance
3. Measure the volume with drainage method, then measure the diameter, calculate the sectional area and length

The length of thin copper wire is as long as several hundred meters, so it is very inconvenient to measure it directly. How to measure it indirectly by balance or scale

First cut 1 meter and weigh it, then weigh the total weight. The total weight is divided by 1 meter

There is a balance, a ruler and a pair of scissors. With them, we can measure the length of a coil of thin iron wire, whether it can be done, and how to do it?

Use the balance to measure the weight of the total wire M0, then cut off a section of wire, weigh the mass M1, and measure the length L
Expression: total length of thin wire L = (M0 * l) / M1