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?
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