ESCAPE VELOCITY

[Audio] Hi everyone Today our topic is Escape velocity.

[Audio] Escape velocity can be defined as The initial velocity which A projectile must have at the earth surface In order to move out of earth gravitational field Is known as escape velocity..

[Audio] Work done in lifting a body from earth surface To a very far off distance into space Which we call absolute potential energy The absolute potential energy is given by G M e m By r e Where M e is the mass of earth R e is the radius of earth M is the mass of object that is displaced And G is the gravitational field constant.

[Audio] If a projectile is given an initial kinetic energy equal to absolute potential energy it will reach an infinite distance from earth Such a projectile will have escape velocity The value of escape velocity can be computed by equating the initial kinetic energy with absolute potential energy..

[Audio] The kinetic energy is given by Half m v square equal to absolute potential energy G M e m By r e Equating equations we get V escape equal to Under root 2 G m e By r e As gravitational force become equal to weight of object We find the value of g m e That becomes equal to g r e square Put values in above equations we get V escape equal to under root 2 g r e.

[Audio] Where g equal to six point six seven multiply Ten raised power minus eleven newton metre square per kilogram square R e equal to six point four multiply Ten raised power six meter M e equal to six multiply ten raised power twenty four kilogram Substituting values we get Value of escape velocity is eleven point two multiply Ten raised power three metre per second The escape velocity is different from different planet.

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