In the same body the energy can be kept at the same time in several forms. The form of all its energy expressed in all forms is called total energy. Some processes proceed in such a way that in their course the total energy of a body almost does not change, and only the ratio of types of energy in it changes.
Instruction
1. Energy is called the size characterizing motions of bodies and their joint interaction. Depending on a type of the movement the energy takes various forms: kinetic, potential, internal, electromagnetic, etc. However, in the majority of tasks of dynamics and kinematics consider kinetic and potential energy. The sum of these two sizes is the total energy which is required to be found in many such tasks.
2. To find total energy as it is stated above, it is necessary to calculate separately both kinetic, and potential energy in the beginning. Kinetic energy is an energy of mechanical motion of a system. Speed of the movement at the same time is fundamental size, and the it is more, the more kinetic energy of a body. The formula for calculation of kinetic energy is provided below: E=mv^2/2 where m-body weight, kg, v is the speed of a moving body, m/s. From this formula it is possible to draw a conclusion that the value of kinetic energy depends not only on speed, but also on weight. Cargo of bigger weight at the same speed has bigger energy.
3. The potential energy is also called energy of rest. It is the mechanical energy of several bodies which is characterized by interaction of their forces. The size of potential energy is proceeding from body weight, however, unlike the previous case, it does not move anywhere, that is, its speed is equal to zero. The case when the body hangs over the Earth's surface at rest is most widespread. At the same time the formula of potential energy will have an appearance: P=mgh where m is kg body weight, and h is height at which there is a body, m. It is also necessary to pay attention that the potential energy not always has positive value. If, for example, it is necessary to define to learn potential energy of the body which is underground, then it will accept negative value: P=-mgh
4. Total energy is result of summation kinetic and potnetsialny. Therefore the formula for its calculation can be written down as follows: Eo=E+P=mv^2/2+mgh. In particular, both types of energy the flying body at the same time has, and, the ratio between them during different phases of flight changes. In a zero reference point the kinetic energy prevails, then in process of flight a part it will be transformed to potential, and at the end of flight kinetic starts over again prevailing.