The acceleration due to gravity on the Earth's
surface is g. If R is the
radius of the Earth, what
is the acceleration due to
gravity at a height 2R above
the Earth?

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

are there options? cause you ain’t. real specific

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.