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प्रश्न
State the law of conservation of energy.
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उत्तर
According to the law of conservation of energy, energy can neither be created nor can it be destroyed. It only changes from one form to another.
संबंधित प्रश्न
A boy weighing 25 kgf climbs up from the first floor at height 3 m above the ground to the third floor at height 9m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N kg -1)
Choose one or more correct alternatives.
Joule is the unit of ______.
- force
- work
- power
- energy
What is the work done when the object acted upon by a force remains at rest?
Name the type of energy possessed by a
(i) stretched catapult (ii) hot iron
(iii) wound up clock
Fill in the boxe to show the corresponding energy transformation.
State the energy changes which take place when Water stored in the dam is used to turn turbine in dynamo.
(i) A 200g ball is thrown vertically upward with an initial velocity of 30 ms-1. Draw a velocity-time graph for the motion of ball.
(ii) How long will the ball take to reach the highest point?
(iii) What will be the kinetic energy of ball, when it returns to the starting point, neglecting the air resistance?
(iv) What will be the potential energy of ball at highest point?
Mention whether work is done or not in the following activity.
| S. No | Activity | Work done or not done |
| 1. | Pushing the door | |
| 2. | Holding a doll | |
| 3. | Sitting in a bus | |
| 4. | Pushing a wall | |
| 5. | Digging soil |
