A chamber contains one barrel of oil and adequate air for the complete burning of the oil, that is, the transformation of the compound molecules of carbon and hydrogen in the oil into molecules of carbon dioxide and water. the burning of 1 barrel of oil makes available about 6 x 10 6 kJ of … Read more
In the United States about 80 quads (1 quad = 10 15 Btu) or about 84 x 1015 kJ of energy is consumed each year. Approximately one-fourth of this energy is transformed into electricity and, on the average, about 3 units of energy are needed per unit of electricity. (a) If all the energy were derived … Read more
An important task in everyday life is the pumping of water from underground wells. Among other methods, this can be carried out either by human effort or by a machine. We wish to compare the energy costs of these two methods of pumping 10,000 kg from a depth of 100 m. Assume that a person … Read more
About 2000 years ago, the most advanced societies around the Mediterranean Sea and around the Chinese Sea used various forms of non-animal energy for their everyday tasks, including the burning of wood for drying and heating, the burning of organic and inorganic oils for lighting, and the capture of winds for propulsion. It has been … Read more
An apple in good condition is placed in a room filled with ordinary air. Without mu effort the apple may be sliced into two pieces. (a) What is the type of state of the entire apple and air system at some time during the first day the apple is placed in the room and before … Read more
A system consists of a battery in a fixed–volume container. the battery has a very large but finite internal electrical resistance and, as a result, slowly but spontaneously discharges with time. Assume that the battery has only two independent properties: energy E and charge C. Typically, the charge is measured in ampere–hours. From the descriptions … Read more
A system consists of carbon, C, oxygen, O2, and carbon dioxide, CO2 confined in a fixed volume, airtight, perfectly isolated container. For each of the descriptions below, indicate the type of state of the system. (a) Measurements are made from time to time, and it is found that the amount of free oxygen is continuously decreasing. … Read more
A large amount of water (1011 kg) is constrained to be in a water pond at a height of 500 m above sea level. At some location, a valve connects the pond to the sea through a long duct and a water turbine. (a) How would you define a system to study the hydropower capabilities of … Read more
The Wilson “cloud chamber” is used to detect and visualize trajectories of charged particles or x–rays. Water vapor mixed with air and other gases is first subjected to a rapid, undisturbed expansion to a volume about 25% greater than the volume at which condensation of vapor would occur. Initiation of condensation requires a small but … Read more
The change in available energy from iron ore to steel is 6.3 x 106 kJ/ton of steel, that is, the available energy of 1 ton of steel is higher by 6.3 x 10 6 kJ than the appropriate quantity of iron oxide from which it is extracated. the available energy of the fuel used in steelmaking … Read more
