Question 185572
One approach to this problem is to imagine that the copper pipe is split down its length and laid open to give you a rectangular prism whose height is the same as the length of the pipe (14cm) and whose length is the same as the outside circumference of the copper pipe ({{{2*pi*r}}}) and the width is the thickness of the copper pipe which can be expressed in terms of the difference of the external radius and the internal radius ({{{R[o]-r[i]}}}).
The volume of such a prism is given by:
{{{V = L*W*h}}} where: {{{L = 2*pi*R[o]}}}, {{{W = R[o]-r[i]}}}, and h = 14cm.
Substituting V = 748, we get:
{{{748 = (2*pi*9)*(R[o]-r[i])(14)}}} Simplifying this:
{{{748 = 252*pi*(R[o]-r[i])}}} Divide both sides by {{{252*pi}}}
{{{0.945 = R[o]-r[i]}}}
The thickness of the copper pipe is 0.945cm