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प्रश्न
Choose one or more correct alternatives.
Which of the forces involved in dragging a heavy object on a smooth, horizontal surface, have the same magnitude?
- The horizontal applied force
- gravitational force
- reaction force in vertical direction
- force of friction
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उत्तर
The gravitational force and the reaction force in the vertical direction have the same magnitude. Friction is not action as the horizontal surface is smooth.
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संबंधित प्रश्न
What is the acceleration of free fall?
A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity just before touching the ground.
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When an object is dropped from a height, it accelerates and falls down. Name the force which accelerates the object.
State whether the following statement is true or false :
A falling stone also attracts the earth.
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.
A force of 15 N acts on a body of mass 2 kg. Calculate 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 The force is then withdrawn and the body moves with a velocity of 2 m s-1.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.
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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 do you understand by the free fall?
The value of gravitational acceleration (g) is ________.
Free fall of an object does not depend on the mass of the object.
Write acceleration due to gravity value on the surface of Earth.
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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?
