One method to measure the diameter of a star is to use an object like the moon or a planet to block out its light and to measure the time it takes to cover up the object. why is this method used more often with the moon rather than the planets, even though there are more planets?

An insulated thermos contains 148 g of water at 72.7 ˚c. you put in a 11.7 g ice cube at 0.00 ˚c to form a system of ice + original water. the specific heat of liquid water is 4190 j/kg•k; and the heat of fusion of water is 333 kj/kg. what is the net entropy change of the system from then until the system reaches the final (equilibrium) temperature?