Efficiency of an Inclined Plane

Power

. 

                                                            POWER

                                            Power = Work = Energy Transferred       

                                                            Time            Time

                  

                                                Time must be in seconds

1.         A light bulb converts 500 J of electrical energy into heat and light in

            5 seconds. What is its power rating?

2.         An electric kettle converts 210,000 J of electrical energy into heat energy in 1       minute. Calculate its power rating?

3.         A person of weight 500 N climbs a 5m flight of stairs in 100 s. Calculate the          power produced.

4.         A car of mass 500 kg is driven up an incline of vertical height 5m in 5s.      Calculate the power output of the engine.

            [Gravitational field strength = 10 N/kg]

5.         Calculate the energy transferred by a 300 W TV in 25 seconds.

6.         Calculate the energy transferred by a 0.0002 W calculator in 5 minutes.

7.         A hoist motor develops 500 W. It does 1000 J of work in lifting a mass.        How long does it take to lift the mass?

8.         A car develops 44 kW. It does 1980 kJ of work in travelling a certain

            distance. How long does this take?

WORK