BRITNEY SPEARS: Heat or Work? 1. The problem statement, all variables and given/known data 1. Which of the following represent a change in an object's thermal energy due to the flow of heat, rather than work being done on the object? You may choose more than one response. a. Liquid nitrogen poured on a slab of ice boils furiously. Liquid nitrogen boils at 77 K. b. A meteorite entering the earth's atmosphere becomes white hot. c. A hot cup of tea rapidly cools on a wintry day. d. A drill bit gets hot as it drills a hole through a hardened steel alloy. 2. A 150-g granite stone is heated to an initial temperature of 100 degrees Celsius. It is then placed in an insulated tub holding 150 g of water at 0 degrees Celsius. The water will cool down the granite so that the final temperature of both is 50 degrees Celsius. a. True b. False 2. The attempt at a solution 1. Well, I think that the answer is b, and c B and c seem to involve temperature differences while d is clearly work flowing across the object's boundary, i'm not so sure about a, which seems to be an intentional kind of work 2. True Tf-Ti = 150-100 = 50?