For a solid propellant rocket motor with a sea‐level thrust of 207,000 lbf, determine: (a) the (constant) propellant mass flow rate and the specific impulse Is at sea level, (b) the altitude for optimum nozzle expansion as well as t

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.