escape velocity (1 Viewer)

[kamakaze]

hi i need help with a question
explain how work done and kinetic energy is used to calculate escape velocity
all help will be greatly aprreciated

 

[whitnall8]

The escape velocity of an object is acheived when it has a net energy of zero, so when it's kinetic energy is equal and opposite to its gravitational potential energy, so equating GMm/r^2 and 1/2(mv^2) will give the escape velocity

 

[addikaye03]

The escape velocity of an object is acheived when it has a net energy of zero, so when it's kinetic energy is equal and opposite to its gravitational potential energy, so equating GMm/r^2 and 1/2(mv^2) will give the escape velocity

So the quoted is saying:

* Bit of an error, GPE=-GMm/r (haven't looked at it in ages, might be wrong but i'm pretty sure GPE tapers linearly w.r.t r)

When 1/2(mv^2)-GMm/r=0

GMm/r=1/2(mv^2)

2GMm/r=mv^2

2GM/r=v^2

therefore v=rt(2GM/r) --- Equation to calculate escape velocity.

See OP?

Note: From here, we know that s=d/t or v=2pir/T, try equating 2pir/T and rt(GM/r), see what formula you end up with

 

[whitnall8]

Yeah ur right thats my bad

GPE = -GMm/r, not -GMm/r^2

 

[addikaye03]

Yeah ur right thats my bad

GPE = -GMm/r, not -GMm/r^2

You will never forget that now lol and that's ok dude, you had the explanation exactly right