91Ó°ÊÓ

Length of hollow cylindrical copper pipe = 1.50 m

Outer diameter of cylindrical copper pipe = 3.50cm =$3.50×{10}^{-2}m$

Inner diameter of cylindrical pipe = 2.50 cm =$2.50×{10}^{-2}m$

Density is ratio of mass of object and volume of object.

In other words, the mass of a fluid per unit volume is its definition.

$\mathrm{ÒÏ}=\frac{m}{V}$…………… (i)

Weight is defined as product of mass and acceleration due to gravity.

How much an item weighs for a given volume is determined by its density.

W = mg…………. (ii)

Volume of hollow cylindrical copper pipe,

$V=\mathrm{Ï€}\left(R_2^2-R_1^2\right)L$

Here,$R_2$is outer radius.

$R_1$ is inner radius.

L is length of hollow cylinder.

Substitute values in above equation,

$V=\mathrm{π}\left[{\left(1.75×{10}^{−2}\right)}^2−{\left(1.25×{10}^{−2}\right)}^2\right]\left(1.50\mathrm{m}\right)=7.06×{10}^{−4}{\mathrm{m}}^3$

Mass of hollow cylinder can be found by using equation(i),

m = pV

Substitute value in above equation we get,

$m=\left(8.9×{10}^3\mathrm{kg}/{\mathrm{m}}^3\right)\left(7.06×{10}^{−4}{\mathrm{m}}^3\right)=6.29\mathrm{kg}$

Weight can be found by using equation(ii),

W = mg

Substitute value in above equation we get,

$W=\left(6.29\mathrm{kg}\right)\left(9.81\mathrm{m}/{\mathrm{s}}^2\right)=61.7\mathrm{N}$

Thus, weight of the hollow cylinder is 61.7N