Question

A steel pipe 100 cm long has an outside diameter of 2 cm and an inside diameter of 1.8 cm. If thee density of the steel is 7.8 grams per cm^3, what is the mass of the pipe to the nearest gram?

Answer 1

Answer:

The mass of the pipe is $465\ g$

Step-by-step explanation:

step 1

Find the volume of the steel pipe

The volume is equal to the area of outside circle minus the area of inside circle, multiplied by the length of the pipe

so

$V=\pi [r2^{2}-r1^{2}]L$

we have

$r2=2/2=1\ cm$ ---> the radius is half the diameter

$r1=1.8/2=0.9\ cm$ ---> the radius is half the diameter

$L=100\ cm$

$\pi=3.14$

substitute

$V=(3.14)[1^{2}-0.9^{2}](100)=59.66\ cm^{3}$

step 2

Find the mass

The mass is equal to the density multiplied by the volume

so

$m=7.8(59.66)=465\ g$