A 200 g aluminum calorimeter can contain 500 g of water at 20 C. A 100 g piece of ice cooled to -20 C is placed in the calorimeter. a. Find the final temperature of the system, assuming no heat losses. (Assume that the specific heat of ice is 2.0 kJ/kg K)
b. A second 200 g piece of ice at -20 C is added. How much ice remains in the system after it reaches equilibrium?
c. Would your answer to part b be different if both pieces of ice were added at the same time?

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?