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प्रश्न
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उत्तर
Kinetic energy of a body depends upon:
(i) Mass of the body
(ii) Speed of the body
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संबंधित प्रश्न
When do we say that work is done?
A coolie is moving on a road with a luggage on his head. Does he perform work against the force of gravity? Give reason for your answer.
State the energy transformation on the following:
Electricity is obtained from solar energy.
When do we say that work is done? Write the formula for the work done by a body in moving up against gravity. Give the meaning of each symbol which occurs in it.
Name the physical quantity whose SI unit is Nm.
Why is less effort needed to lift a load over an inclined plane as compared to lifting the load directly?
A man climbs a slope and another walks same distance on level road. Which of the two expends more energy and why?
A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
(i) How much force would be needed to lift a drum into the truck directly/without using the plank? (Take g = 10 m/s2)
(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
A water pump raises 50 kg of water through a height of 25 m in 5s. Calculate the power supplied by the pump (Take: g = 10 N kg−1).
