We can classify machines into two groups, according to the number of parts they have: _______ machines and _______ machines.
simple; complex
_______ machines have one or two parts.
Simple
_______ machines have many parts.
Complex
We can classify machines into three groups, according to the type of energy they use: _______ machines, _______ machines, and _______ machines.
manual; electrical; thermal
A _______ is a group of elements that can support load.
structure
Structures have one or more horizontal _______ for the load.
girders
Structures have vertical _______ to support the load.
pillars
What do we use to lift a load?
a lever
We use _______ or effort to move a load.
force
A rigid bar moves over a point called a _______.
fulcrum
The fulcrum of a Class 1 lever is _______ the load and the force.
between
The _______ of a Class 2 lever is between the fulcrum and the force.
load
We apply the _______ of a Class 3 lever between the fulcrum and the load.
force
