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प्रश्न
Write a short note.
Free Fall
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उत्तर
- The motion of any object under the influence of the force of gravity alone is called free fall.
- In free fall, the initial velocity of the object is zero and goes on increasing due to the acceleration due to 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.
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संबंधित प्रश्न
Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall faster than a light object?
What is the acceleration of free fall?
A stone is allowed to fall from the top of a tower 100 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25 m/s. Calculate when and where the two stones will meet.
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.
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)
What do you understand by the term 'acceleration due to gravity of earth' ?
Why does a sharp knife cut objects more effectively than a blunt knife ?
Name the force which wears away two surfaces as they move over one another.
Name the force which pulled the apple off Isaac Newton’s tree.
Solve the problem.
If the mass of a planet is eight times the mass of the Earth and its radius is twice the radius of the Earth, what will be the escape velocity for that planet?
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?
The value of acceleration due to gravity of earth :
What is the acceleration due to gravity?
In vacuum, all freely falling objects have the same force. Is it true?
Explain why:
Objects fall to the earth.
The free fall of an object is possible only in _______.
The value of gravitational acceleration at the centre of earth is zero.
Calculate the escape velocity on the surface of the moon given the mass and radius of the moon to be 7.34 × 1022 kg and 1.74 × 106 m respectively.
(Given: G = 6.67 × 10-11 Nm2/kg2)
When is free fall possible?
