Explain how the movements of electrons in electric conductors and electric insulators affect the properties of the materials

Ahorizontal force of 400.0 n is required to pull a 1760 n truck across the floor at a constant speed. find the coefficient of sliding friction.

Point charges q1=+2.00μc and q2=−2.00μc are placed at adjacent corners of a square for which the length of each side is 1.50 cm . point a is at the center of the square, and point b is at the empty corner closest to q2. take the electric potential to be zero at a distance far from both charges. part a what is the electric potential at point a due to q1 and q2? express your answer with the appropriate units.

How long will it take a car traveling of a constant speed of 45m/s to cover the distance of a 2.5km?