Why is electrical wiring usually made from copper ?

What is hidden during a lunar eclipse? isn't the moon hidden?

Aplane takes off from an airport and flies to town a, located d1 = 215 km from the airport in the direction 20.0° north of east. the plane then flies to town b, located d2 = 230 km at 30.0° west of north from town a. use graphical methods to determine the distance and direction from town b to the airport. (enter the distance in km and the direction in degrees south of west.)

Which of the following is the main energy source for the sun? a. fission of hydrogen b. fusion of hydrogen c. fusion of helium d. fission of iron