Work is called the energy developed or spent for some period of action of a physical system. As well as energy, work is measured in joules. But also stand-alone units, for example kilowatt-hours can sometimes be used.
Instruction
1. Before calculations transfer all basic data to the SI system (tension - in volts, current - in amperes, force - in newtons, speed - in meters per second, time - in seconds and so on).
2. Calculate the power consumed or developed by a physical system. The way of its calculation depends on at what principle this system works. For example, if it is electric, increase current by tension: P=UI where P is power, W, U is tension, In, I - current, And. If the system is mechanical, increase force applied to an object by the speed which it as a result of it gathers: P=FS where P is power, W, F is force, the N, S is the speed, m/s.
3. Increase the power allocated or absorbed by a physical system for a period during which it worked (or by a part of this interval for which you wish to learn perfect work): A=Pt where A is work, J, P is power, the W, t is time, page. At the same time consider, the watt-second is the same, as joule therefore if in statements of the problem it is told that the result has to be expressed in watt-seconds, the additional translation of units will not be required.
4. If the result needs to be expressed in kilowatt-hours, divide it into 3600000: P [kWh] = P [J]/3600000