The Earth is approximately a sphere of diameter 12742 km. The surface area of a sphere is given by the formula A = 4π r² Calculate the surface area of the Earth. Give your answer in metres squared and in standard form. (Take pi = 3.142) *

5.101 x 10^14 m^2

Step-by-step explanation:

First you have to convert km to metres (the final answer must in metres).

So that would be 12742000m. Remember this is the diameter. The radius is half the diameter. So the radius would be 6371000m.

You then put it into the formula: 4 x π x 6371000².

And then you would get the 5.101 x 10^14 m^2

step-by-step explanation:

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.