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प्रश्न
Explain what is meant by the equation :
`g= Gxxm/r^2`
where the symbols have their usual meanings.
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उत्तर
g = GM /R2
This is an equation , which expresses acceleration due to gravity. It states that acceleration due to gravity (g) can be calculated as a product of the Gravitational Constant (G), which is 6.673 × 10−11 Nm2 kg−2 and mass of the planet (M) i.e., 5.98 × 1024 kg in case of the earth divided by square of radius of that planet (R), i.e., 6.4 ×106 m for earth. This is an equation, which expresses acceleration due to gravity. By putting the respective values for earth, g can be calculated as 9.8 m/s2.
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संबंधित प्रश्न
What do you mean by the term free fall ?
A force acts for 10 s on a stationary body of mass 100 kg, after which the force ceases to act. The body moves through a distance of 100 m in the next 5 s. Calculate : The acceleration produced by the force
Define the term acceleration due to gravity? Write its S.I. unit.
How is the acccelaration due to gravity on the surface of the earth realted to its mass and radius ?
A body falls freely under gravity from rest and reaches the ground in time t. Write the expression for the height fallen by the body.
In vacuum, all freely falling objects have the same force. Is it true?
Explain why:
Objects fall to the earth.
Write a short note.
Free Fall
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?
When is free fall possible?
