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संबंधित प्रश्न
A water pump raises 50 litres of water through a height of 25 m in 5 s. Calculate the power of the pump required.
(Take g = 10 N kg-1 and density of water = 1000 kg m-3)
A car is running at a speed of 15 km h-1 while another similar car is moving at a speed of 45 km h-1. Find the ratio of their kinetic energies.
Why does a spanner have a long handle?
State the energy changes which take place when A stone dropped from the top of a cliff reaches the ground after some time.
In what way does an ‘Ideal machine’ differ from a ‘Practical machine’?
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.
Write the two main conditions are needed for work to be done?
