Point A is 2.50 m from a +3.73*10^-8 C charge, and Point B is 1.00 m from the charge. What is the potential difference when you go from point A to point B? Include the correct sign, + or - (Hint: Does V go up or down when you go from A to B?) (Unit = V)​

A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.