A copper wire (density = 8.96g/cm^3) has a diameter of 0.25mm. If a sample of this copper wire has a mass of 22g, how long is the wire?
Does anybody know how to do this problem? I can't figure it out and it's driving me crazy!!
Thanks :-)
2007-04-23 02:22:25 · 3 answers · asked by Anonymous in Education & Reference ➔ Homework Help
First answer has the principle right, but got the decimal point in the wrong place for the wire diameter. The answer is more like 5,011cm. Note that since the previous answer used 2.5cm for the diameter instead of .25mm, (probably misread as .25m instead of .25mm) which is 100 times too big, the correct answer is 100^2 or 10,000 times the previous answer
2007-04-23 03:03:21 · answer #1 · answered by tinkertailorcandlestickmaker 7 · 0⤊ 0⤋
Convert diameter to centimeters for like units.
0.025 mm = 0.0025 cm
Radius = 0.0025/2 cm = 0.00125 cm
Volume of cylinder (wire) = Pi*r^2*L
3.1416*(0.0025^2)*L cubic cm = volume
The volume is 22g / 8.96g/cubic cm
or about 2.455 cubic cm
Now substitute back into the volume formula,
3.1416*(0.0025^2)*L cubic cm = 2.455 cubic cm
L=125,031.83 cm
Check my arithmetic. It is basically a cylinder problem, just need to get everything in like units.
2007-04-23 09:55:06 · answer #2 · answered by Robert L 7 · 0⤊ 0⤋
density = 8.96 g/cm^3
D = 2.5 cm
m = 22 g
Volume = m/density = 22 g/(8.96 g/cm^3) = 2.46 cm^3
Volume also equals pi * radius^2 * Length
2.46 cm^3 = 3.14 * (2.5 cm/2)^2 * L (in cm)
Length = 0.5 cm
2007-04-23 09:38:07 · answer #3 · answered by thubanconsulting 3 · 0⤊ 0⤋