Experienced 2703

The customer wants to buy 300 meters of wire with d = 4mm. An experienced salesman knows that 100 meters of wire are about 10 kilograms, so he weighs 30 kilograms of wire. Find out how many meters of wire are in a bundle of wire weighing 30 kilograms (or there will be about 300 meters) if one cubic meter of wire weighs 7800 kilograms.

Correct answer:

x =  306.0672 m

Step-by-step explanation:

$$\begin{gathered} h=7800 \\ d=4 \\ r=d/2/1000=4/2/1000=\frac{1}{500}=0.002 \\ m=30 \\ x=m/(h\cdot \pi \cdot r^2)=30/(7800\cdot 3.1416\cdot 0.002^2)=306.0672\text{m} \end{gathered}$$

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