During an investigation, a scientist heated 123.6 g of copper carbonate till it decomposed to form a black residue. The total mass of the black residue formed was 79.6 9. Does the law of conservation of mass hold true in this case? Use complete sentences to justify your answer based on numerical calculations.

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?