Advertisements
Advertisements
प्रश्न
The total energy of an object falling freely towards the ground ______.
विकल्प
decreases
remains unchanged
increases
increases in the beginning and then decreases
Advertisements
उत्तर
The total energy of an object falling freely towards the ground remains unchanged.
Explanation:
In an object falling freely to the ground, as the object's distance from the ground decreases, so does the potential energy stored in the object; But the kinetic energy of a freely falling object increases as the velocity increases over time. Thus, the potential energy lost by an object in free fall is equal to the kinetic energy it gains, i.e. the total energy of the object remains constant.
APPEARS IN
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.
What is the acceleration produced in a freely falling body of mass 10 kg ? (Neglect air resistance)
State whether the following statement is true or false :
A falling stone also attracts the earth.
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.
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 stops you falling through the floor.
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.
For freely falling object we can write the Newton’s second equation of motion as …..
The value of acceleration due to gravity of earth :
The acceleration produced in a body by a force of given magnitude depends on
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?
Define the term acceleration due to gravity? Write its S.I. unit.
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
In vacuum, all freely falling objects have the same force. Is it true?
Write scientific reasons.
The value of gravitational acceleration (g) decreases as we go deep inside the earth.
Define acceleration due to gravity.
Write a short note.
Escape Velocity
The mass and weight of an object on earth are 5 kg and 49 N respectively. What will be their values on the moon? Assume that the acceleration due to gravity on the moon is 1/6th of that on the 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?
