What is vigorous activity? a any activity or exercise performed most days of the week, preferably daily b any activity or exercise that ranges in intensity from heavy-to-maximum exertion c any activity that ranges in intensity from light-to-borderline-exertion

Explain why electric current cannot exist if a current doesn't have a voltage source.

Electric field of the earth. the earth has a net electric charge that causes a field at points near its surface equal to 150 n> c and directed in toward the center of the earth. (a) what magnitude and sign of charge would a 60-kg human have to acquire to overcome his or her weight by the force exerted by the earth’s electric field? (b) what would be the force of repulsion between two people each with the charge calculated in part (a) and separated by a distance of 100 m? is use of the earth’s electric field a feasible means of flight? why or why not?

Which of the following is not a transverse wave? a) soundb) lightc) radiod) all of thesee) none of these