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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 it 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
A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate
- the maximum height to which it rises.
- the total time it takes to return to the surface of the earth.
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.
Which force is responsible for the moon revolving round the earth ?
What is the acceleration produced in a freely falling body of mass 10 kg ? (Neglect air resistance)
What force is responsible for the earth revolving round the sun ?
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.
Explain why, if a stone held in our hand is released, it falls towards the earth.
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 ?
A stone is thrown vertically upwards with initial velocity u reaches a height ‘h’ before coming down. Show that the time taken to go up is the same as the time taken to come down.
What will be the weight of a person on earth, who weighs 9N on the moon?
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 :
How are g and G realated ?
A body is projected vertically upward with an initial velocity u . If acceleartion due to gravity is g , the time for which it remains in air , is :
What is the acceleration due to gravity?
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’.
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)
