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प्रश्न
State two advantage of producing hydroelectricity.
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उत्तर
Advantages of producing the hydroelectricity:
1. It does not produce any environmental pollution.
2. It is a renewable source of energy.
संबंधित प्रश्न
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?
A man lifts a mass of 20 kg to a height of 2.5 m. Assuming that the force of gravity on 1 kg mass is 10 N, find the work done by the man.
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.
A coolie is pushing a box weighing 1500 N up an inclined plane 7.5 m long on to a platform, 2.5 m above the ground.
(i) Calculate the mechanical advantage of the inclined plane. (ii) Calculate the effort applied by the coolie.
(iii) In actual practice, the coolie needs to apply more effort than what is calculated. Give one reason why you think the coolie needs to apply more effort.
An electric motor of power 100 W is used to drive the stirrer in a water bath. If 50% of the energy supplied to the motor is spent in stirring the water. Calculate the work done on the water in one minute.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.
State whether work is done or not, by writing yes or no, in the following case:
A man pushes a wall.
