When solid surfaces slide over each other, the kind of friction that occurs is called sliding friction true or false?

Apositive rod is placed to the left of sphere a, and the spheres are separated. which best describes the spheres? sphere a is negative and sphere b is positive because protons from sphere a are attracted to the rod and move to sphere b. sphere a is negative and sphere b is positive because electrons from sphere b are attracted to the rod and move to sphere a. sphere a is positive and sphere b is negative because electrons from the rod move to sphere b and protons then move to sphere a. sphere a is positive and sphere b is negative because protons move from sphere b to the rod and also to sphere a.

The slope of a velocity time graph over any interval of time gives the during that interval

Which lists the pairs of plates in order from least to greatest in terms of the work done to move the electron?