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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?
State whether the following statement is true or false :
The acceleration due to gravity acting on a freely falling body is directly proportional to the mass of the body.
Fill in the following blank with suitable word :
The acceleration due to gravity on the moon is about ………………of that on the earth.
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.
Why does a sharp knife cut objects more effectively than a blunt knife ?
Explain why, a wide steel belt is provided over the wheels of an army tank.
An object thrown vertically upwards reaches a height of 500 m. What was its initial velocity? How long will the object take to come back to the earth? Assume g = 10 m/s2
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.
A force acts for 0.1 s on a body of mass 2.0 kg initially at rest. The force is then withdrawn and the body moves with a velocity of 2 m s-1. Find the magnitude of the force.
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
What is the acceleration due to gravity?
The free fall of an object is possible only in _______.
Free fall of an object does not depend on the mass of the object.
Write scientific reason.
The value of gravitational acceleration (g) decreases as we go deep inside the earth.
Define 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’.
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?
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?
