8. The Coulomb’s law states that the force of attraction or repulsion between two electrically charged particles (point charges) is proportional
to the product of their charges and inversely proportional to the square of
the distance between them. An alpha particle 4 comes within 80 Fermi of
a gold nucleus (197). Assuming that gold nucleus and the alpha particle 79
are point charges, find the maximum repulsive force.

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.