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प्रश्न
Define 1 watt of power.
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उत्तर
1 watt is the power of an agent which does 1 joule of work in 1 second.
In other words, if the rate of energy use is 1 J s-1, then the power is 1 W.
1 watt = `(1 "joule")/(1 "second")`
or 1 w = 1 Js-1
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संबंधित प्रश्न
A load of 100 kg is pulled up by 5 m. Calculate the work done. (g = 9.8 m/s2)
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(i) the amount of work done
(ii) potential energy of the body at that height (value of g = 10 m/s2)
How much is the mass of a man if he has to do 2500 joules of work in climbing a tree 5 m tall? (g = 10 m s−2)
Name the physical quantity whose unit is watt.
The power output of an engine is 3kW. How much work does the engine do in 20 s?
An electric heater uses 600 kJ of electrical energy in 5 minutes. Calculate its power rating.
A car of weight 20000 N climbs up a hill at a steady speed of 8 m/s, gaining a height of 120 m is 100 s. Calculate : work done by the car.
A boy weighing 40 kg carries a box weighing 20 kg to the top of a building 15 m high in 25 seconds. Calculate the power. (g = 10 m/s2)
In an experiment to measure his power, a student records the time taken by him in running up a flight of steps on a staircase. Use the following data to calculate the power of the student :
Number of steps = 28
Height of each step = 20 cm
Time taken = 5.4 s
Mass of student = 55 kg
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due to gravity
In loading a truck, a man lifts boxes of 100 N each through a height of 1.5 m.
If the man lifts 4 boxes per minute, at what power is he working?
(g = 10 m s−2)
