Equilibrium of Non-Concurrent Forces Lab

1. What are the two conditions for equilibrium of a rigid body? How would this experiment demonstrate their validity?

2. In part 3, you can calculate the moment of the known mass and use that to determine the unknown mass, but explain how the unknown mass can be determined without directly calculating the torque (hint: use ratios).

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?