To the nearest watt, what is the minimum power required for a conveyor to raise a box weighing 8 newtons 4 meters vertically in 8 seconds?

Describe the path of a ray that approaches a mirror parallel to the principal axis.

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.

The direction of the current in an alternating current circuit remains constant. is direct. changes repeatedly. changes randomly.