40. An electric motor raises a load of 0.2 kg, at a constant speed, through a vertical distance of 3.0 m in 2: the acceleration of free fall is 10 m/s2, the power in W developed by the motor in raising the load is :

(a) 0.3
(b) 1.2
(c) 3.0
(d) 6.0
41. An object is falling freely from a height x. After it has fallen a height, it will possess :
(h) only kinetic energy

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.