Which calculation will determine power

This means that for every extra joule that is transferred per second, the power increases by one watt. Two electric motors are used to lift a 2 N weight through a vertical height of 10 m. Motor one does this in 5 seconds. Motor two does this in 10 seconds. For both motors, the energy transferred - the work done - is 20 J. For motor one:. If you want to calculate electric power, try our Ohm's law calculator. In Physics, work performed by an object is understood as the amount of energy that needs to be supplied to move by a certain distance.

For example, it can be the energy required to carry heavy bags up the stairs or the kinetic energy resulting in the movement of the body. Generally, it is calculated as force multiplied by the displacement an object travels. Precisely speaking, it's a dot product between these two quantities. Speaking of joules, you might find our nm to joules converter an interesting read. Power is the rate of change of work or the amount of work done in a certain amount of time.

The higher the power of a device, the more work it can perform in a given time period. For some real-life applications of power, check out the cycling wattage calculator!

Embed Share via. The cost of using the computer in this example is neither exorbitant nor negligible. It is clear that the cost is a combination of power and time. When both are high, such as for an air conditioner in the summer, the cost is high.

The motivation to save energy has become more compelling with its ever-increasing price. Armed with the knowledge that energy consumed is the product of power and time, you can estimate costs for yourself and make the necessary value judgments about where to save energy. Either power or time must be reduced. It is most cost-effective to limit the use of high-power devices that normally operate for long periods of time, such as water heaters and air conditioners.

This would not include relatively high power devices like toasters, because they are on only a few minutes per day. It would also not include electric clocks, in spite of their hour-per-day usage, because they are very low power devices. It is sometimes possible to use devices that have greater efficiencies—that is, devices that consume less power to accomplish the same task.

One example is the compact fluorescent light bulb, which produces over four times more light per watt of power consumed than its incandescent cousin. Modern civilization depends on energy, but current levels of energy consumption and production are not sustainable. The likelihood of a link between global warming and fossil fuel use with its concomitant production of carbon dioxide , has made reduction in energy use as well as a shift to non-fossil fuels of the utmost importance.

Even though energy in an isolated system is a conserved quantity, the final result of most energy transformations is waste heat transfer to the environment, which is no longer useful for doing work. Skip to main content. Work, Energy, and Energy Resources. Search for:. Power Learning Objectives By the end of this section, you will be able to: Calculate power by calculating changes in energy over time. Examine power consumption and calculations of the cost of energy consumed.

Power Power is the rate at which work is done. Example 1. Calculating the Power to Climb Stairs What is the power output for a Example 2. Calculating Energy Costs What is the cost of running a 0. Discussion The cost of using the computer in this example is neither exorbitant nor negligible. Conceptual Questions Most electrical appliances are rated in watts.