They would most likely use statistics on the increase/decrease in population from previous decades and centuries. In addition to these statistics, they could use the birth and death rate and ultimately predict the increase within these next 30 years. They must also take climate change and other environmental factors into consideration when formulating such a bold prediction.
Answer:
Electromagnetic cranes are used to separate copper from iron in a scrap yard. The current is switched on to energies the electromagnet and pick up the iron pieces from the scrap. Then these iron pieces are moved to another position, the electromagnet in switched off and the iron pieces are released.
Explanation:
Answer:
Gravity varies when the Earth rotates and its mass and density differ based on where you are on the planet. Knowing how gravity affects sea level thus aids geodesists in making more precise calculations. The mean sea level would be higher in parts of the earth where gravitational forces are heavier.
Explanation:
Answer:
Given the area A of a flat surface and the magnetic flux through the surface 
it is possible to calculate the magnitude 
.
Explanation:
The magnetic flux gives an idea of how many magnetic field lines are passing through a surface. The SI unit of the magnetic flux is the weber (Wb), of the magnetic field B is the tesla (T) and of the area A is (
). So 1 Wb=1 T.m².
For a flat surface S of area A in a uniform magnetic field B, with 
being the angle between the vector normal to the surface S and the direction of the magnetic field B, we define the magnetic flux through the surface as:
We are told the values of and B, then we can calculate the magnitude
