Question

What does a mechanical advantage less then one mean? What is gained?

Answer 1

A mechanical advantage less than ' 1 ' means the output force is less than the input
force. But distance is gained ... the load moves farther than the driving force moves.

An example of all this is a big father and his little 4-year-old daughter playing
on the see-saw in the park.  He adjusts the board so that he's much closer
to the pivot than she is, and that way, their weights can balance each other.

It's set up so that the mechanical advantage from him to her is less than ' 1 '.
Now, look at what happens when Dad sits down on his end of the see-saw,
and pushes it down with his 180 pounds of force.  At the other end, the board
is barely lifting her with a force of just 30 pounds.  BUT ... as he sinks down
only 1 foot against his end of the board, her end rises 6 feet off the ground.