#Power formula physics generator

This tells us that something other than voltage determines the power output of an electric circuit. Although both operate at the same voltage, the 60-W bulb emits more light intensity than the 25-W bulb. Let us compare a 25-W bulb with a 60-W bulb (see Figure 19.20). To get started, let’s think of light bulbs, which are often characterized in terms of their power ratings in watts. In this section, we’ll learn not only what this means, but also what factors determine electric power.

Power is the rate at which energy of any type is transferred electric power is the rate at which electric energy is transferred in a circuit. We also use electric power to start our cars, to run our computers, or to light our homes. Electric power transmission lines are visible examples of electricity providing power. Every day, we use electric power to run our modern appliances.

(a) What is the average useful power output of a person who does 6.00 × 10 6 J of useful work in 8.00 h? (b) Working at this rate, how long will it take this person to lift 2000 kg of bricks 1.Power is associated by many people with electricity.

h of energy per day? (b) How many joules of energy does this appliance consume in a year?.

(a) What is the average power consumption in watts of an appliance that uses 5.00 kW.

What is the cost of operating this air conditioner 3.00 h per day for 30.0 d if the cost of electricity is $0.110 per kW

A large household air conditioner may consume 15.0 kW of power.

What is the cost of operating a 3.00-W electric clock for a year if the cost of electricity is $0.0900 per kW.

#Power formula physics generator

Neglecting any problems of generator efficiency and practical considerations such as resting time: (a) How many people would it take to run a 4.00-kW electric clothes dryer? (b) How many people would it take to replace a large electric power plant that generates 800 MW? A person in good physical condition can put out 100 W of useful power for several hours at a stretch, perhaps by pedaling a mechanism that drives an electric generator.Note that there are on the order of 10 11 observable galaxies, the average brightness of which is somewhat less than our own galaxy. Using data from Table 1: (a) By what factor does its power output increase? (b) How many times brighter than our entire Milky Way galaxy is the supernova? (c) Based on your answers, discuss whether it should be possible to observe supernovas in distant galaxies.

Suppose a star 1000 times brighter than our Sun (that is, emitting 1000 times the power) suddenly goes supernova.

Crab Nebula (credit: ESO, via Wikimedia Commons)

The power of many devices such as electric motors is also often expressed in horsepower (hp), where 1 hp = 746 W.įigure 4.

At the bottom of the stairs, we take both KE and PE g as initially zero thus, W= ext\. The work going into mechanical energy is W= KE + PE. Her power output depends on how fast she does this. When this woman runs upstairs starting from rest, she converts the chemical energy originally from food into kinetic energy and gravitational potential energy.