Usually the pipe has the form of a hollow cylinder therefore its weight depends on wall thickness, material of production and length. If these parameters are given in statements of the problem, the decision it will come down to finding of a formula in a general view, substitution of values of variables and to calculation of result. For practical calculations of mass of a pipe as industrial product of value of variables it is possible to learn from normative documents - state standard specifications.
Instruction
1. For drawing up a formula of calculation of mass of a pipe it is necessary to learn the cross-sectional area of a hollow cylinder. That to make it, the wall thickness (a) has to be known. If it is not in statements of the problem, but (D) diameters are given internal (d) and external, express wall thickness through a half of a difference of these sizes: a = (D-d)/2. Determine cross-sectional area as the difference between the work of external diameter increased by number by Pi on wall thickness and a wall thickness square: π * (D*a-a²).
2. Using a cross-sectional area formula, determine the volume concluded between external and internal walls - increase the formula received on the previous step by length (L) pipe: π * (D*a-a²) * L.
3. To receive a final formula of calculation of mass (m) of a hollow cylinder, it was necessary to consider material of which the pipe is made. For this purpose increase a formula from the previous step by density (ρ): m = π * (D*a-a²)*L*ρ.
4. Substitute in a value formula, provided in statements of the problem, and calculate result. At the same time consider dimension of initial sizes. Let's say the external diameter of a steel pipe is equal to 30 cm, wall thickness is 5 mm, length - 4 m, and steel density - 7.95 g/cm³. In this case it is possible to substitute in a formula all sizes in centimeters, to receive result in grams and to transfer it to kilograms: 3.14 * (30*0.5-0.5²)*400*7.95 = 3.14*14.75*400*7.95 = 147281.7 g ≈ 147.3 kg.
5. In practical calculations for determination of values of variables which need to be substituted in a formula use the marking applied on pipes or specified in accompanying documents. Knowing it, it is possible to determine the necessary sizes by normative documents - to state standard specifications. For example, density of steel pipes can be learned from GOST 9941-8, and density of plastic is specified in GOST 18599-2001.
6. If to you enough approximate values, it is possible to use online calculators - the reference to one of them is given below. This service allows to count the mass of pipes from eight types of metals.