BBC Bitesize - GCSE Combined Science - Work, power and efficiency - AQA - Revision 1
In physics we say that work is done on an object when you transfer energy to that use of electric power over a period of time expressed in kilowatt-hours (kWh). In physics, work is related to the amount of energy transferred to or from a system by a . Average power is the average amount of work done per unit of time. Learn about and revise energy and how it's related to work, power and efficiency with GCSE Bitesize Combined Science.
The equation for power shows the importance of time: Special attention should be taken so as not to confuse the unit Watt, abbreviated W, with the quantity work, also abbreviated by the letter W. Combining the equations for power and work can lead to a second equation for power. A few of the problems in this set of problems will utilize this derived equation for power.
Power (video) | Work and energy | Khan Academy
Mechanical, Kinetic and Potential Energies There are two forms of mechanical energy - potential energy and kinetic energy. Potential energy is the stored energy of position. In this set of problems, we will be most concerned with the stored energy due to the vertical position of an object within Earth's gravitational field. Kinetic energy is defined as the energy possessed by an object due to its motion. An object must be moving to possess kinetic energy.
The amount of kinetic energy KE possessed by a moving object is dependent upon mass and speed. The total mechanical energy possessed by an object is the sum of its kinetic and potential energies. Work-Energy Connection There is a relationship between work and total mechanical energy. The final amount of total mechanical energy TMEf possessed by the system is equivalent to the initial amount of energy TMEi plus the work done by these non-conservative forces Wnc.
Difference Between Energy and Power
The mechanical energy possessed by a system is the sum of the kinetic energy and the potential energy. Positive work is done on a system when the force doing the work acts in the direction of the motion of the object.Work, Energy, and Power: Crash Course Physics #9
Negative work is done when the force doing the work opposes the motion of the object. When a positive value for work is substituted into the work-energy equation above, the final amount of energy will be greater than the initial amount of energy; the system is said to have gained mechanical energy. When a negative value for work is substituted into the work-energy equation above, the final amount of energy will be less than the initial amount of energy; the system is said to have lost mechanical energy.
- Work, power and efficiency - AQA
- Power (physics)
- Work, Power, and Energy
There are occasions in which the only forces doing work are conservative forces sometimes referred to as internal forces.
Typically, such conservative forces include gravitational forces, elastic or spring forces, electrical forces and magnetic forces. When the only forces doing work are conservative forces, then the Wnc term in the equation above is zero.
Power (physics) - Wikipedia
In such instances, the system is said to have conserved its mechanical energy. The proper approach to work-energy problem involves carefully reading the problem description and substituting values from it into the work-energy equation listed above. Inferences about certain terms will have to be made based on a conceptual understanding of kinetic and potential energy.
For instance, if the object is initially on the ground, then it can be inferred that the PEi is 0 and that term can be canceled from the work-energy equation. In other instances, the height of the object is the same in the initial state as in the final state, so the PEi and the PEf terms are the same. As such, they can be mathematically canceled from each side of the equation.
When a neutron splits an atom's nucleus into smaller pieces it is called fission. When two nuclei are joined together under millions of degrees of heat it is called fusion Electrical Energy --The generation or use of electric power over a period of time expressed in kilowatt-hours kWhmegawatt-hours NM or gigawatt-hours GWh.
Chemical Energy --Chemical energy is a form of potential energy related to the breaking and forming of chemical bonds. It is stored in food, fuels and batteries, and is released as other forms of energy during chemical reactions.
Mechanical Energy -- Energy of the moving parts of a machine. Also refers to movements in humans Heat Energy -- a form of energy that is transferred by a difference in temperature What is Power Power is the work done in a unit of time.
Mechanics: Work, Energy and Power
In other words, power is a measure of how quickly work can be done. One common unit of energy is the kilowatt-hour kWh. If we are using one kW of power, a kWh of energy will last one hour.
Power's unit of measurement in the English system is the horsepower, which is equivalent to How much work is done? Please enter your answer in the space provided: How much power is used?