Originally Posted by
brandtzag
Flintstone:
Perhaps you would kindly explain "kinetic" energy an why the engines, if moving at the same speed as the airframe, suddenly appears ahead.
I'm always willing to learn something new. Especially when it comes to physics.
F=ma
Heavy things (like engines) have more momentum. Objects in motion tend to stay in motion. Objects with more mass require more force to decelerate them than objects with less mass. Its really simple Newtonian physics.
The object (the total aircraft) will act at the center of gravity until shearing forces tear the object into multiple centers of gravity. Each new center of gravity will have its own momentum. High mass (high density) objects will have a lot of momentum and less surface area and the arresting forces provided by inelastic collisions(bouncing, rolling, digging into the ground, twisting), friction and will provide minimal retardation to motion relative to the momentum.
Think feathers falling vs. bowling balls falling in air. Or 'rolling' on the ground.