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प्रश्न
What is escape velocity?
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उत्तर
The minimum velocity required to project an object to escape from the Earth's gravitational pull is known as escape velocity. It is given as: vesc = `sqrt((2"GM")/"R")`
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संबंधित प्रश्न
What do you mean by free fall?
What do you mean by acceleration due to gravity?
Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall faster than a light object?
A ball thrown up vertically returns to the thrower after 6 s. Find
- the velocity with which it was thrown up,
- the maximum height it reaches, and
- its position after 4 s.
What force is responsible for the earth revolving round the sun ?
State whether the following statement is true or false :
A falling stone also attracts the earth.
Explain what is meant by the equation :
`g= Gxxm/r^2`
where the symbols have their usual meanings.
Explain why, a wide steel belt is provided over the wheels of an army tank.
Name the force which stops you falling through the floor.
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What would be the value of ‘g’ on the surface of the earth if its mass was twice and its radius half of what it is now?
A force of 10 N acts on a body of mass 5 kg. Find the acceleration produced.
How is the acccelaration due to gravity on the surface of the earth realted to its mass and radius ?
How are g and G realated ?
What is the acceleration due to gravity?
The mass and weight of an object on earth are 5 kg and 49 N respectively. What will be their values on the moon? Assume that the acceleration due to gravity on the moon is 1/6th of that on the earth.
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.
1) 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.
2) Why does free fall not happen on the earth?
3) Why does the velocity of the object increase during the free fall?
4) Which type of force exerts on the object during free fall?
5) Why does free fall happen only in a vacuum?
