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प्रश्न
Explain by an example that a body may possess energy even when it is not in motion.
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उत्तर
A body can have energy even if it is not in motion. The statement can be justified by:
Water stored in the reservoir at the roof of a building possesses gravitational potential energy due to its position above the ground.
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संबंधित प्रश्न
A coolie does no work against the force of gravity while carrying a luggage on a road.
Each of the following statement describes a force acting. Which force is causing work to be done?
Explain the difference between a uniform linear motion and a uniform circular motion.
A block of mass 20 kg is pulled up a slope (fig.12) with a constant speed by applying a force of 500 N parallel to the slope. A and B are initial and final positions of the block.
(a) Calculate the work done by the force in moving the block from A and B.
(b) Calculate the potential energy gained by the block.
Why is less effort needed to lift a load over an inclined plane as compared to lifting the load directly?
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?
