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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
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?
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.
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)
Name the force which pulled the apple off Isaac Newton’s tree.
What will be the weight of a person on earth, who weighs 9N on the moon?
i) If g = GM/r2 then where will the value of g be high at Goa Beach or on top of Mount Everest?
A metal ball of mass 5 kg falls from a height of 490 m. How much time it will take to reach the ground? (g = 9.8 m/s2)
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
A force causes an acceleration of 10 m s-2 in a body of mass 500 g. What acceleration will be caused by the same force in a body of mass 5 kg?
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.
Explain why:
Objects fall to the earth.
Right or wrong sentence.
Free fall of an object does not depend on the mass of the object.
Define acceleration due to gravity.
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?
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?
