escape velocity (1 Viewer)

[velox]

can someone explain it cos my book is so crap at explaining it

 

[zenger69]

Escape velocity is the minimum vertical velocity needed to escape the gravitational field of a planet.

So it's like saying the minimum speed needed to escape or get out of something like Earth's gravitational pull.

And you can work this out using the root gm formula which i don't know how to type up.

 

[velox]

ok my bad, i meant to say for ppl to explain how it says that if you throw a projectile from a tall tower at a pretty quick speed it will go into orbit. I get that, but then it says something about the earth falling away, so the projectile never lands on the earth. Thats the bit i dont get =/

 

[FinalFantasy]

ok my bad, i meant to say for ppl to explain how it says that if you throw a projectile from a tall tower at a pretty quick speed it will go into orbit. I get that, but then it says something about the earth falling away, so the projectile never lands on the earth. Thats the bit i dont get =/

i think it just means.. if u throw a projectile at a slow speed.. it will just land on the earth somewhere.. but if u throw it fast enough... it will go past the curve of da earth and keep going instead of landing on da earth, therefore it keep going and going(orbit).. (correct me if im wrong lol)

 

[zenger69]

I think there's that newton experiment thats in most textbooks.

Firing the cannon on the cliff.

He found that higher the initial velocity greater the range.

But if you fire it at greater initial velocity, it will become orbital velocity, as space is a vacuum and objects travelling in space keep doing what they are already doing. Therefore the object when in orbit will travel at the same speed and direction.

EXCEPT the gravitational pull of the Earth is like centripetal force, pulling this orbital object already at speed down to Earth. Therefore it orbits in a circle.

And if you fire at an even greater initial velocity, it would escape the gravtitational pull fo Earth.

I hope this helps. Post back if your still stuck.