Apr 14 2010
Energy Math: Scribe Post
There are four basic math problems that we have to know for the exam. These problems deal with basic algebra so there is NO need for a calculator.
Energy/Power:
When dealing with these problems, you must remember that energy is the ability to work and power is a rate. For power, P=E/T and the units are in watts. For energy, E=P x T and the units are in Joules.
Heat Transfer:
This is important for active heating. Why do we need to know this? Any time we use energy, we need to heat the water that turns our turbines and generators. This formula seems difficult but is quite easy, Q=mc(delta)T. This quation is equal to calories or BTU( British Thermal Units). The m stands for the mass, the c is the specific heat of water, which is equal to one, and the delta time, is the change in temperature. When solving these problems units are a key factor and will cost you points if you forget them!
Price:
These problems deal with very simple algebra, but sometimes the problems can come across confusing. It has a basic formula of #units x price/unit=price($). These problems are easy to do in your head, but when you do them on paper writing down the units can help you determine your answer. This becomes important when you are doing your energy bills at home.
Energy Efficiency:
These problems become important when you are trying to determine how efficient the light bulb you are using may be. The efficiency can never be 100% because of the second law of thermodynamics, in the energy transfer, some energy is always lost in heat. The formula for these problems is input=output/efficiency. Normally efficiency is given in a percentage so you just need to convert it to a decimal to use it in the problem.
