Estimate the current density in copper wire at 20 °C if an electric field of 0.923 V/m exists within the wire.

In what direction does the medium move relative to the direction of the wave? explain.

Idon’t quite understand this problem

Mutt and jeff are running along a path each pushing a cart loaded with rocks. if mutt's wagon has a mass two times greater than jeff's and they want to stay together, arriving at their destination at the same time, what must happen? a) jeff should slow down so mutt can catch up. b) mutt must use half as much force to push his cart. c) mutt must use twice as much force to push his cart. d) mutt and jeff will use the same force, but mutt will take bigger steps.