Question

A cubic inch of PVC material weight 0.063 pounds per cubic inch. What’s the weight of a 36 inch piece of PVC pipe with an outside diameter of 0.82 inches and an inside diameter of 0.75 inches?

A. 0.678 pounds
B. 0.783 pounds
C. 0.598 pounds
D. 0.814 pounds

Answer 1

Option B. 0.783 pounds

Explanation:

step 1

Find the area of a a 36 inch piece of PVC pipe with an outside diameter of 0.82 inches and an inside diameter of 0.75 inches

The area of a circle is equal to

`A=\pi r^(2)`

we have

`r2=0.82\ in`

`r1=0.75\ in`

assume

`\pi =3.14`

`A=\pi (r2^2-r1^2)`

substitute the values

`A=(3.14)(0.82^2-0.75^2)`

`A=0.345086\ in^2`

step 2

Find the volume of the piece of PVC

Multiply the area by its length

`V=0.345086(36)=12.42\ in^3`

step 3

Find the weight of the piece of PVC

Multiply the volume by its density

The density is
`0.063(lb)/(in^3)`

so

`W=12.42(0.063)=0.783\ lb`