One easy way to reduce heating (and cooling) costs is to add extra insulation in the attic of a house. Suppose a single-story cubical house already had 15 cm of fiberglass insulation in the attic and in all the exterior surfaces. If you added an extra 8.0 cm of fiberglass to the attic, by what percentage would the heating cost of the house drop? Take the house to have dimensions 10 m by 15 m by 3.0 m. Ignore air infiltration and heat loss through windows and doors, and assume that the interior is uniformly at one temperature and the exterior is uniformly at another.

A 0.250-kg aluminum bowl holding 0.800 kg of soup at 25.0 is placed in a freezer. What is the final temperature if 388 kJ of energy is transferred from the bowl and soup, assuming the soup's thermal properties are the same as that of water?

A 100-g piece of copper, initially at 95.0C, is dropped into 200 g of water contained in a 280-g aluminum can; the water and can are initially at 15.0C. What is the final temperature of the system? (Specific heats of copper and aluminum are 0.092 and 0.215 cal/g C. respectively.) (a) 16C (b) 18C (c) 24C (d) 26C (e) none of those answers

On a cold winter morning, why does the metal of a bike feel colder than the wood of a porch?

A warms transfers energy by conduction through its blubber at the rate of 150 W when immersed in 1.00 water. The walrus's internal core temperature is 37.0 and it has a surface area of 2.00 m2. What is the average thickness of its blubber, which has the conductivity of fatty tissues without blood?

Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 20 rubs, at a distance of 7.50 cm per nub, and with an average frictional force of 40.0 N, what is the temperature increase? The mass of tissues warned is only 0.100 kg, mostly in the palms and fingers.

(a) The number of kilocalories in food is determined by calorimetry techniques in which the food is burned and the amount of heat transfer is measured. How many kilocalories per gram ale there in a 5.00-g peanut if the energy from burning it is transferred to 0. 500 kg of water held in a 0.100-kg aluminum cup, causing a 54.9- temperature increase? Assume the process takes place in an ideal calorimeter, in other words a perfectly insulated container. (b) Compare your answer to the following labeling information found on a package of dry roasted peanuts: a sewing of 33 g contains 200 calories. Comment on whether the values are consistent.

Why is a person able to remove a piece of dry aluminum foil from a hot oven with bare fingers, whereas a burn results if there is moisture on the foil?

Most automobiles have a coolant reservoir to catch radiator fluid than may overflow when 1he engine is hot. A radiator is made of copper and is filled to its 16.0L capacity when at 10.0C. What volume of radiator fluid will overflow when the radiator and fluid reach their 95.0C operating temperature, given that the fluid’s volume coefficient of expansion is =400106/C ? Note that this coefficient is approximate, because most car radiators have operating temperatures of greater than 95.0C.