The mechanical advantage of the lever is that smaller persons can move heavier objects. The lever can be placed under the object and the person can then push down on the lever.
Mechanical advantage is the factor by which a force or torque is multiplied.
Mechanical advantage is not the only reason to use levers.
functional levers
Levers are a big deal when it comes to Mouse Trap Cars, levers help make the mechanical advantage and ideal mechanical advantage higher and better.
They don't, they just give you a mechanical advantage.
Common mechanisms for obtaining mechanical advantage would include such as multiple pulleys, hydraulic systems, gears, and levers.
Mechanical Advantage [achieved through levers or pulleys]
lenght of the effort arm divided by lenght of the load arm
wheel gears electricity levers mechanical advantage
Archimedes work on levers brought about the concept of torque. He used levers and pulleys to illustrate mechanical advantage. Torque and moments make us understand the mechanical concepts.
The spokes of a wheel are comparable to levers. Longer spokes give more mechanical advantage. Even in a wheel that is solid, and has no spokes, the greater the diameter, the greater the mechanical advantage.
The load is the weight and the effort is the movment. The effort is the force applied, and load divided by effort is mechanical advantage.
Because that's what levers do. It's like with gears, a long and weak movement can be traded for a shorter and stronger movement.