commercial unit of energy Work and Energy-Science - Class 9
Because energy is defined via work, the SI unit for energy is the same as the unit of work – the joule (J), named in honor of James Prescott Joule and his experiments on the mechanical equivalent of heat. In slightly more fundamental terms, 1 joule is equal to 1 newton metre and, . Thermodynamic system · Thermodynamic state · Thermodynamic potential. The commercial unit of energy is a. joule. c. kilojoule-hour. 5. 1 kWh is terms of energy. 4. Explain the concept of average power. 5. Derive the relationship between SI unit of electrical energy and commercial unit of energy. How is the . the commercial unit of energy = kilo watt hour = x10^6 J (1 kilo watt x 1 hour) .
The source-to-site ratios for natural gas and fuel oil burned in a building are much lower than the source-to-site ratio for electricity produced at a fuel-burning power plant.
In the case of the house that uses , Btu of site energy each year the example given aboveit might require 40, kWh of coal in other words, , Btu of coal to generate 12, kWh of electricity for the house. Moreover, it might require 70, Btu of energy to deliver 69, Btu of fuel oil to the house. The Energy Star program assumes the following source-to-site ratios based on national averages: In other words, it takes 1. Another source provides the following source-to-site ratios for the U.
Average energy use per person A nonprofit group in Switzerland, the 2,Watt Societyhas calculated that the current level of worldwide energy use amounts to 2, watts per capita.
Unit of Electrical Energy
The work done by a force will be negative if that force or a component of that force points in the opposite direction as the displacement. If a force points in a direction that's perpendicular to the displacement, the work done by that force is 0, which means it's neither giving nor taking away energy from that object.
Another way that the work done by a force could be 0 is if the object doesn't move, since the displacement would be 0. So the force you exert by holding a very heavy weight above your head does not do any work on the weight since the weight is not moving. So this formula represents the definition of the work done by a particular force.
But what if we wanted to know the net work or total work done on an object? We could just find the individual amounts of work done by each particular force and add them up. But there's actually a trick to figuring out the net work done on an object.
To keep things simple, let's assume that all the forces already lie along the direction of the displacement. That way we can get rid of the cosine theta term.
Since we're talking about the net work done on an object, I'm going to replace F with the net force on that object. Now, we know that the net force is always equal to the mass times the acceleration. So we replace F net with m times a. So we find that the net work is equal to the mass times the acceleration times the displacement.
I want to write this equation in terms of the velocities and not the acceleration times the displacement.
Second, compounds derived from incomplete catabolism of protein are lost in the urine.
Work and the work-energy principle (video) | Khan Academy
Third, the capture of energy conversion to adenosine triphosphate [ATP] from food is less than completely efficient in intermediary metabolism Flatt and Tremblay, Conceptually, food energy conversion factors should reflect the amount of energy in food components protein, fat, carbohydrate, alcohol, novel compounds, polyols and organic acids that can ultimately be utilized by the human organism, thereby representing the input factor in the energy balance equation.
This energy is referred to as ingested energy IE or gross energy GE. Incomplete digestion of food in the small intestine, in some cases accompanied by fermentation of unabsorbed carbohydrate in the colon, results in losses of energy as faecal energy FE and so-called gaseous energy GaE in the form of combustible gases e.
Short-chain volatile fatty acids are also formed in the process, some of which are absorbed and available as energy. Most of the energy that is absorbed is available to human metabolism, but some is lost as urinary energy UEmainly in the form of nitrogenous waste compounds derived from incomplete catabolism of protein.
A small amount of energy is also lost from the body surface surface energy [SE]. Not all metabolizable energy is available for the production of ATP. Some energy is utilized during the metabolic processes associated with digestion, absorption and intermediary metabolism of food and can be measured as heat production; this is referred to as dietary-induced thermogenesis DITor thermic effect of food, and varies with the type of food ingested.
This can be considered an obligatory energy expenditure and, theoretically, it can be related to the energy factors assigned to foods. When the energy lost to microbial fermentation and obligatory thermogenesis are subtracted from ME, the result is an expression of the energy content of food, which is referred to as net metabolizable energy NME.
Adapted from Warwick and Baines and Livesey in press [a].
Commercial Unit of Energy
Some energy is also lost as the heat produced by metabolic processes associated with other forms of thermogenesis, such as the effects of cold, hormones, certain drugs, bioactive compounds and stimulants. In none of these cases is the amount of heat produced dependent on the type of food ingested alone; consequently, these energy losses have generally not been taken into consideration when assigning energy factors to foods.
The energy that remains after subtracting these heat losses from NME is referred to as net energy for maintenance NEwhich is the energy that can be used by the human to support basal metabolism, physical activity and the energy needed for growth, pregnancy and lactation. By contrast, net metabolizable energy NME is based on the ATP-producing capacity of foods and their components, rather than on the total heat-producing capacity of foods.
The theoretical appeal of NME for the derivation of energy conversion factors rests on the following: These differences in efficiency are reflected in the differences between heat production from each substrate and that from glucose; they can be determined stoichiometrically and can be measured.