A student discovers an unknown white powder in a laboratory. He decides to measure and collect data on the following properties in an effort to identify the white powder. His
observations are recorded in the data table above.
• Make a claim about which of the following properties would be most useful in
identifying the powder.

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?