While standing at the edge of the roof of a building, a man throws a stone upward with an initial speed of 7.19 m/s. the stone subsequently falls to the ground, which is 20.1 m below the point where the stone leaves his hand. at what speed does the stone impact the ground? ignore air resistance and use =9.81 m/s² for the acceleration due to gravity.

Identical marbles are released from the same height on each of the following four frictionless ramps . compare the speed of the marbles at the end of each ramp. explain your reasoning

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

To understand the behavior of the electric field at the surface of a conductor, and its relationship to surface charge on the conductor. a conductor is placed in an external electrostatic field. the external field is uniform before the conductor is placed within it. the conductor is completely isolated from any source of current or charge. part a: which of the following describes the electric field inside this conductor? it is in the same direction as the original external field. it is in the opposite direction from that of the original external field. it has a direction determined entirely by the charge on its surface. it is always zero. part b: the charge density inside the conductor is: 0non-zero; but uniformnon-zero; non-uniforminfinite part c: assume that at some point just outside the surface of the conductor, the electric field has magnitude e and is directed toward the surface of the conductor. what is the charge density η on the surface of the conductor at that point? express your answer in terms of e and ϵ0