A3.7-kg block on a horizontal frictionless surface is attached to an ideal spring whose force constant (spring constant) is 450 n/m. the block is pulled from its equilibrium position at x = 0.000 m to a position x = +0.080 m and is released from rest. the block then executes simple harmonic motion along the horizontal x-axis. the maximum elastic potential energy of the system is closest to

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.