A20 m high filled water tank develops a 0.50 cm hole in the vertical wall near the base. with what speed does the water shoot out of the hole? a) 30 m/s
b)15 m/s
c) 25m/s
d) 20 m/s

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.