So basically the objects would be sandpaper and smooth metal, the sandpaper can indirectly touch the metal since it’s so smooth and it won’t cause any temp change either
The current is defined as the amount of charge Q that passes through a given point of a wire in a time

:

Since I=500 A and the time interval is

the charge is

One electron has a charge of

, therefore the number of electrons that pass a point in the wire during 4 minutes is

electrons
A baby carriage is sitting at the top of a hill that is 21m high. The carriage with the baby weighs 12N. The carriage has... energy. Calculate it = <span>252J</span>