by cricketjeff on May 24, 2009. © Jeff Green, All rights reserved
It just comes down to energy
Potentially from gravity
Kinetic from velocity.
Old Isaac was the first who dared
To get this concept widely shared
We’ll do this first to get prepared
Take half your mass by speed that’s squared
That was “kinetic” by the way
So now “potential” must make play
Take G times what both bodies weigh
Divide by separation, ‘Kay?
Now if the former bests the latter
You can escape from all my chatter
But when the other way around
My friend you’re stuck here on the ground!
The potential energy is the energy you’d get if you fell all the way to the centre of gravity of an object, it can be calculated by G(the gravitational constant) times your weight times the Earth’s weight (if it is you trying to escape Earth) divided by the distance your centre of gravity is from the Earth’s.
Kinetic energy is half your mass (weight is an expression of mass if gravity doesn’t change) times your speed squared (I know the formula says velocity but velocity is speed in a direction and energy has no direction).
And as with just about everything in science in the end it is all down to energy, the biggest bang wins!