There is a bundle of wires of uniform thickness made of metal of density P. Xiao Ming measured its total length with a platform scale, pencil and scale Please help him write out the experimental steps and the mathematical expression of the total length of the wire

There is a bundle of wires of uniform thickness made of metal of density P. Xiao Ming measured its total length with a platform scale, pencil and scale Please help him write out the experimental steps and the mathematical expression of the total length of the wire

1. The total mass of conductor measured by platform scale is m
2. Wrap the lead tightly around the pencil and count the number of turns n
3. Use a scale to measure the length of the wire around the pencil (not to measure it, but to measure it parallel to the pencil), and count it as L
Conductor diameter: D = L / n
Cross sectional area s = 0.25 π D & # 178; = 0.25 π (L / N) &# 178;
M = PV = PSL total
L total = m / PS = 4N & # 178; m / P π L & # 178;

If a metal bar with uniform thickness is cut into two sections and the ratio of the length of the two sections is 2:1, the ratio of the mass to the density of the two sections is

Mass 2:1, density 1:1