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प्रश्न
Observe the picture and put a tick (✓) if work is done and put a cross (x) if work is not done.
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उत्तर
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संबंधित प्रश्न
Write true or false of the following statement.
In an electric fan, electrical energy changes into the mechanical energy.
Write true or false of the following statement.
One form of energy cannot be converted into another form.
Match the following:
| Column A | Column B |
| (a) Needle | (1) class II lever |
| (b) Doorknob | (2) inclined plane |
| (c) Ramp | (3) Class I lever |
| (d) Lemon crusher | (4) Wheel and axle |
| (e) Seesaw | (5) wedge |
Derive the relation between commercial unit of energy (kWh) and SI unit of energy (joule).
- Take two aluminium channels of different lengths.
- Place the lower ends of the channels on the floor and hold their upper ends at the same height.
- Now take two balls of the same size and weight and release them from the top end of the channels. They will roll down and cover the same distance.
- At the moment of releasing the balls, which energy do the balls have?
- As the balls roll down which energy is converted into which other form of energy?
- Why do the balls cover the same distance on rolling down?
Note: The question is wrong. It should be "Why do the balls cover the same distance after rolling down"? - What is the form of the eventual total energy of the balls?
- Which law related to energy does the above activity demonstrate? Explain.
Can you tell?
What should be taken into account for measuring work?
We make useful objects from a variety of substances. Another use of substances is that we get energy from some of them.
When we have run a long distance, we feel tired. We have to stop. Why is that?
Running water possesses ______.
When a body falls freely towards the earth, then its total energy
Define kilowatt hour.
