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प्रश्न
When is free fall possible?
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उत्तर
Free fall is only conceivable in the absence of air or vacuum. When a ball and a feather are thrown from a height, the ball falls to the ground first. In a vacuum, both the ball and the feather will end up on the ground.
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संबंधित प्रश्न
What do you mean by 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.
What force is responsible for the earth revolving round the sun ?
During a free fall, will heavier objects accelerate more than lighter ones ?
What is the usual value of the 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.
For freely falling object we can write the Newton’s second equation of motion as …..
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
The total energy of an object falling freely towards the ground ______.
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 The force is then withdrawn and the body moves with a velocity of 2 m s-1.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.
A car is moving with a uniform velocity 30 ms-1. It is stopped in 2 s by applying a force of 1500 N through its brakes. Calculate the following values : The retardation produced in car.
How are g and G realated ?
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.
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
Right or wrong sentence:
The value of gravitational acceleration at the centre of earth is zero.
Right or wrong sentence.
Free fall of an object does not depend on the mass of the object.
Write the acceleration due to gravity value on the surface of Earth.
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?
