A simple explanation might be weight (or mass) acting through a distance (inches, centimeters, etc) creates a force.
Examples:
1.) On a see saw (or teeter-totter) a 100 lb person sitting a 2' from the balance point (or fulcrum) will create a force of 200 lbs.- ft (often and very incorrectly stated as ft-lbs*) match 100 lbs x 2 feet= 200 lb.-ft). A 50 lb. person sitting at the other end of the see saw sitting at 4 feet from the balance point will create the same force and both persons will be in perfect balance. The math 50 lbs. x 4" = 200 lbs. ft.
2.) If the 50 ponder moves 6 feet away from the balance point he will create a greater force (or 300 lb.- ft.) and raise the larger person in the air.

* Yes this is a fact. As they say I are an engineer by degree. Also, a battery sitting on concrete will not discharge any faster than a battery stored on wood, plastic, cardboard, etc. They both will discharge at the same rate. Concrete is not a conductor of electricity but humidity in the air is. Batteries from little lawn tractor batteries to forklift 1200 am/hr batteries are recommended to be charged at least every 6 months if not put into service to 1.) boost voltage to spec 2.) add water that may have evaporated below the top of the plates 3.) to prevent plate sulfating

THE FORKLIFT WORKS ON THE PRINCIPLE OF LOADS BALANCED OVER A FULCRUM.
A SIMPLE EXAMPLE OF A FULCRUM IS A SEE-SAW OR TEETER-TOTTER.
A POINT IN THE EXACT MIDDLE WILL BALANCE THE EQUAL WEIGHTS AT THE ENDS.
THE FULCRUM OF A LOADED TRUCK IS A IMAGINARY VERTICAL LINE THROUGH THE CENTER OF THE DRIVE AXLE HUB.
Not sure if thats where you were going, if I had a marker board I got another couple hours left in me...but then we would all be asleep by then.
Sorry for the shouting, easier to for the old guys that need glasses.