Different between density and realative density

Jessie ran 5000 meters from the cops and an average speed of 6 meters / second before he got caught . how long did he run?

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?

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot