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प्रश्न
State the energy changes which take place when A piece of magnesium wire is burnt in a jar of oxygen.
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उत्तर
Chemical energy (chemical reaction) → Heat energy (burning)
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संबंधित प्रश्न
Work done = Force × ........................................
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Complete the following sentences:
1 H.P. = ........ W.
Can work done be zero even if force acts on the body?
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?
One labourer carried four pans of road metal through a distance of 100 metres. If he carries two pans of road metal through a 200 metre distance ______ work will be done.
