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प्रश्न
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उत्तर
K.E = `1/2` mv2
K.E = `1/2`(2) (20)2
or K.E = 400 J
Thus K.E is 400J
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संबंधित प्रश्न
Define 1 joule of energy.
The work done on an object does not depend on ______.
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The point O lies in the same plane. Given, P = Q = R = 10N
(i) Which force has the least moment about O? Give a reason.
(ii)Which force has the greatest moment about O? Give a reason.
How many joules are there in 1 mega joule?
Name the type of energy possessed by a
(i) stretched catapult (ii) hot iron
(iii) wound up clock
An electric motor drives a machine which lifts a mass of 4 kg through a height of 10 m in 5 s at a constant speed. Assuming g = 10 ms-2, calculate
(i) the amount of work done, (ii) the power of the machine.
Why is less effort needed to lift a load over an inclined plane as compared to lifting the load directly?
A girl of mass 40 kg runs a height of 80 stairs, each 25 cm high with a load of 20 kg on her head in 25 sec. If g is 10 m/s2, find:
(i) Gravitational force acting on the girl.
(ii) Work done by her.
(iii) Useful work done by her.
(iv) Her power in watt.
