An iron pipe has a cross section the iron being 1cm thick ,the mass of 1cm³ of cast iron is 7.2kg . calculate the mass of a 2-metre length of the pipe
To calculate the mass of a 2-meter length of the pipe, we need to determine the volume of the pipe first.
The cross-section of the pipe is 1 cm thick. So, the internal radius of the pipe (i.e., the radius at which the inner surface of the pipe starts) is the external radius minus 1 cm. Let's assume the external radius is "r" cm.
The internal radius would be (r - 1) cm. Therefore, the diameter of the internal circle would be 2 * (r - 1) cm.
The diameter of the external circle (which represents the outer surface of the pipe) would be 2 * r cm.
The cross-sectional area (A) of the pipe is the difference between the areas of the external and internal circles, i.e., (π * (2 * r)^2) - (π * (2 * (r - 1))^2).
Simplifying, the cross-sectional area (A) would be equal to (4πr^2) - (4π(r - 1)^2).
To find the volume (V) of the pipe, we multiply the cross-sectional area (A) by the length of the pipe (2 meters), i.e., V = A * 200 cm^3.
The mass of 1 cm³ of cast iron is given as 7.2 kg.
Therefore, the mass of the 2-meter length of the pipe would be (V * 7.2 kg).