why cannot we escape escapefrom the gravitational force with speed lessthen 11.2km/s?

Question

to escape from gravitational roce just we need to move towards away from earth up to the admosphere'send then why thespeed 11.2km/s is needed

Answer 1

11.2 km/sec is the escape velocity.
below this speed the centripetal force is greater than the cetrifugal firce and you stay put
At this speed the two forces balance each other. Much like neutral equilibrium
Higher than this the centrifugal force is greater that the centripetal force and we will escape the earth's orbit

Answer 2

The earths gravitational force is 9.8m/s-2
weather accleration while falling down or decelleration while going up is 9.8m/-2
Ex: Initially we give a stone an accleration of 58.8m/s-2, then we have overcomed the earths gravitational force and the stone has gone up, so as we cannot go up along with the stone and give it accleration every-time slowly the force which we gave the stone decreases and the gravitational force pulls it down, then slowly the stone goes up with an accleration of 58.8-9.8 m/s-2 = 49m/s-2, but still its force is greater than the gravity and it goes up still, as soon as the force which you gave finishes its accleration becomes
0m/s-2 and then the gravity come into act and pulls the stone back cause the force which u gave finished and became 0 but the gravity which is continuesly there until the force became 0 and brings it down with an accleration of 9.8m/s-2 it slowly increases its accleration become the stone is getting close to the land it first from 0 comes to 9.8 then 19.6 then 29.4 etc. until it reaches the ground.
Now we need a velocity continuesly which is always greater then the gravity pull, here the engines of the rocket always act and the gravity also acts, these engines continuesly maintain its velocity which is more than earth's gravitational pull
In the stone example we cant continuesly be with the stone and maintain its velocity, isint it! But it the rocket the engines always maintain the rockets velocity
thats why 11.2km/s-2 is needed to escape from the earth.

Answer 3

Forces take time to react and gravitational stress is not any distinctive so, if the rate is far less then the reaction time then physique remains attracted as a results of gravitational forces in the direction of the planet. yet on the rate is of 11.2KM/2nd, reaction time is extra then the rate so that's called get away velocity for gravitational stress of earth on a shifting physique.

Answer 4

Thank you for your question, what you say is true, the gravitational force exerted by the Earth on the Moon has to be equal to the centripetal force.

An interesting application of this principle is that it allows you to determine a relation between the period of an orbit and its size. Let us assume for simplicity the Moon's orbit as circular (it is not, but this is a good approximation for our purposes).

The gravitational acceleration that the Moon experience due to the gravitational attraction from the Earth is given by:

ag=G(MEarth+MMoon)/r2

Where G is the gravitational constant, M stands for mass, and r is the radius of the orbit. The centripetal acceleration is given by:

acentr=(4 pi2 r)/T2

Where T is the period. Since the two accelerations have to be equal, we obtain:

(4 pi2 r) /T2=G(MEarth+MMoon)/r2

Which implies:

r3/T2=G(MEarth+MMoon)/4 pi2=const.

This is the so-called third Kepler law, that states that the cube of the radius of the orbit is propprtional to the square of the period.

This has interesting applications. In the Solar System, for example, if you know the period and the radius of one planet orbit, by knowing another planet's period you can determine its orbit radis. I hope that this answers your question.

Answer 5

Newton's law. To move in a direction (up) you have to have momentum that exceeds the pull back (gravity) and it must take resistance of other bodies (air) into account.

If you went to the moon and shot an arrow upwards it might actually escape the pull of the moon's gravity, but on Earth resistance fromt he air slows it down and it starts to fall back.

Answer 6

For speed less than 11.2 Km/s you will come back to earth as stone which we throw in air comes back to earth.