Answer:
The momentum would be doubled
Explanation:
The magnitude of the momentum of the freight train is given by:

where
m is the mass of the train
v is its speed
In this problem, we have that the speed of the train is unchanged, while the mass of the train is doubled:

therefore, the new momentum is

so, the momentum has also doubled.
A scientific law is the simple mathematical expression of the relationship involved. A principle is the same relationship expressed in words. A theory is the explanation of the facts that make up the relationship.
Answer;
It's about acceleration, right?
Answer:
Newtons.
Explanation:
Force is given by the multiplication of mass and acceleration.
Mathematically, Force is;
Where;
F represents force measured in Newton.
m represents the mass of an object measured in kilograms.
a represents acceleration measured in meter per seconds square.
Newtons is a measurement we use to determine the amount of force used to move an object by a simple machine. It is the International System of Units (SI) used to measure force and has a symbol of N.
Basically, it was named after Sir Isaac Newton based on his fundamental works in the field of mechanics (motions).
Reduce friction because friction just makes things harder