By what factor does the force required to stop a car increase if the initial speed is doubled and the stopping distance remains the same?

Is it possible to use the energy from two atoms colliding to create a clean burning lasting fuel source with a large amount of force? is it also possible to harness that energy from the two atoms colliding to create a clean energy source that will last for years from just two atoms colliding. is there a possibility to control and store that energy for years but slowly let the energy out enough to power cities cheaper and faster.

Avalue that describes how heavy an object is and is related to the force of gravity is

Ais a machine that makes work easier when a single force is applied. a simple machine b compound machine c endangered machine d complex machine