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प्रश्न
Write scientific reasons.
When we drop a feather and a stone at the same time from a height the stone reach the earth faster than a feather.
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उत्तर
- When we drop a feather and a heavy stone at the same time from a height, the feather experiences a buoyant force and a frictional force due to air and therefore floats and reaches the ground slowly.
- But the buoyant and frictional forces on the stone are much less than the weight of the stone and does not affect the speed of the stone much.
- Hence, when we drop a feather and a stone at the same time from a height, the stone reach the earth faster than a feather.
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संबंधित प्रश्न
What do you mean by free fall?
What is the acceleration of free fall?
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The acceleration due to gravity acting on a freely falling body is directly proportional to the mass of the body.
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The value of acceleration due to gravity of earth :
How is the acccelaration due to gravity on the surface of the earth realted to its mass and radius ?
What do you understand by the free fall?
The value of gravitational acceleration (g) is ______.
Right or wrong sentence.
Free fall of an object does not depend on the mass of the object.
Write scientific reasons.
The value of gravitational acceleration (g) decreases as we go deep inside the earth.
The mass of planet ‘X’ is four times that of the earth, and its radius is double the radius of the earth. The escape velocity of a body from the earth is 11.2 × 103 m/s. Find the escape velocity of a body from the planet ‘X’.
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Read the given passage carefully and answer the questions.
| We know that the force of gravity due to the earth acts on each and every object. When we were holding the stone in our hand, the stone was experiencing this force, but it was balanced by a force that we were applying on it in the opposite direction. As a result, the stone remained at rest. Once we release the stone from our hands, the only force that acts on it is the gravitational force of the earth and the stone falls down under its influence. Whenever an object moves under the influence of the force of gravity alone, it is said to be falling freely. Thus the released stone is in a free fall. In free fall, the initial velocity of the object is zero and goes on increasing due to the acceleration due to the gravity of the earth. During free fall, the frictional force due to air opposes the motion of the object and a buoyant force also acts on the object. Thus, true free fall is possible only in a vacuum. |
- Complete the following statement by choosing the right option.
The stone held in the hand is stable because on it ......- two unbalanced forces are exerted.
- only the gravitational force of the earth is exerted.
- gravitational force of the earth is not exerted.
- two balanced forces are exerted.
- Why does free fall not happen on the earth?
- Why does the velocity of the object increase during the free fall?
- Which type of force exerts on the object during free fall?
- Why does free fall happen only in a vacuum?
