How can fluid friction be decreased?

Along, straight wire with 3.0 a current flowing through it produces magnetic field strength 1.0 t at its surface. if the wire has a radius r, where within the wire is the field strength equal to 36.0% of the field strength at the surface of the wire? assume that the current density is uniform throughout the wire

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

In a system, when potential energy decreases, then entropy also decreases. true false