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प्रश्न
What do you understand by the free fall?
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उत्तर
Free fall means motion of a body under the gravity of earth only.
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संबंधित प्रश्न
Which force is responsible for the moon revolving round the earth ?
Explain what is meant by the equation :
`g= Gxxm/r^2`
where the symbols have their usual meanings.
During a free fall, will heavier objects accelerate more than lighter ones ?
Give reason for the following :
The force of gravitation between two cricket balls is extremely small but that between a cricket ball and the earth is extremely large.
What is the force of gravity on a body of mass 150 kg lying on the surface of the earth? (Mass of earth = 6 x 1024 kg; Radius of earth = 6.4 x 106 m; G = 6.7 x 10-11 Nm2/kg2)
Figure shows the velocity-time graph of a particle of mass 100 g moving in a straight line. Calculate the force acting on the particle.
(Hint : Acceleration = Slope of the v-t graph)
An object falling freely from rest reaches ground in 2 s. If acceleration due to gravity is 9.8 m s-2, then the velocity of object on reaching the ground will be
Write scientific reason.
When we drop a feather and a stone at the same time from a height the stone reach the earth faster than a feather.
Write a short note.
Escape Velocity
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?
