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प्रश्न
Can there be displacement of an object in the absence of any force acting on it? Think. Discuss this question with your friends and teacher.
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उत्तर
- Yes, there can be displacement in an object in the absence of force. If the object is moving at a uniform speed, then no external force acts on that object, but there is displacement in the object.
- When an object is released in a free state from an inclined plane, it comes down due to the force of gravity, but on reaching the earth's surface, no force acts on it in the horizontal direction.
- That object moves at a uniform speed in the horizontal direction, and displacement keeps occurring in it.
संबंधित प्रश्न
State the S.I. unit of work and define it.
A vessel containing 50 kg of water is placed at a height 15 m above the ground. Assuming the gravitational potential energy at ground to be zero, what will be the gravitational potential energy of water in the vessel? (g = 10 m s-2)
What are the quantities on which the amount of work done depends? How are they related to work?
How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.
Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?
Is the motion of moon around the earth in circular path an accelerated motion?
A block of mass 20 kg is pulled up a slope (fig.12) with a constant speed by applying a force of 500 N parallel to the slope. A and B are initial and final positions of the block.
(a) Calculate the work done by the force in moving the block from A and B.
(b) Calculate the potential energy gained by the block.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A wind-mill is lifting water from a well.
State whether work is done or not, by writing yes or no, in the following case:
A boy climbs up 20 stairs.
