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Matter In Our Surroundings
What do you understand by kinetic energy of a body? Give some examples.
Kinetic energy:
Kinetic energy is the energy possessed by a body by virtue of its motion. Work is done by a moving object.
The amount of work which a moving object can do before coming to rest is equal to its kinetic energy.
Fig. Conversion of energy into kinetic energy by a hammer.
Examples:
(i) A moving hammer drives a nail into the wood. Being in motion, it has kinetic energy or ability to do work, as shown in Fig. above.
(ii) A fast moving stone can break a window pane. The stone has kinetic energy due to its motion and so it can do work.
(iii) The kinetic energy of air is used to run windmills.
(iv) The kinetic energy of running water is used to run water mills.
(v) A bullet fired from a gun can pierce a target due to its kinetic energy.
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Give reason for the following observations.
We can get the smell of perfume sitting several metres away.
What is the physical state of water at
a) 25°C
b)00C
c)1000C
What is the physical state of water at
0°C
What is the physical state of water at
100°C
Give two reasons to justify
Water at room temperature is a liquid.
Give two reasons to justify
An iron almirah is a solid at room temperature.
Why is ice at 273K more effective in cooling than water at the same temperature ?
What produces more severe burns, boiling water or steam ?
8. Name A, B, C, D, E and F in the following diagram showing state change :
Both boiling and evaporation convert a liquid into vapour. What is the difference between the two process
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