When researchers peered at
the knees of the Papuan weevil
recently, they had a surprise
coming to them. Their massive
electron micrographs of the
joint showed tiny, perfectly
formed screws and nuts, with a
thread far more delicate than
those made by humans. The
weevil, it appeared, used them
to lock its knees for stability
when it landed.
What simple machine does
this look like?
This was the first time
scientists had seen such
structures in nature.
A lever is a bar that turns on an unmoving point called a fulcrum. When you push or pull
on one end of the bar that pressure is called the force. The object that is lifted on the
other end is called the load.
There are three parts to all levers:
•
Fulcrum - the point at which the lever rotates.
•
Input force (also called the effort) - the force applied to the lever.
•
Output force (also called the load) - the force applied by the lever to
move the load.
There are three types of levers: first class, second class and third class. The difference
between the three classes depends on where the force, the fulcrum or the load is.
In a first class lever, the fulcrum is located between the input force and output force.
A lever is a bar that turns on an unmoving point called a fulcrum. When you push or pull
on one end of the bar that pressure is called the force. The object that is lifted on the
other end is called the load.
There are three parts to all levers:
•
Fulcrum - the point at which the lever rotates.
•
Input force (also called the effort) - the force applied to the lever.
•
Output force (also called the load) - the force applied by the lever to
move the load.
There are three types of levers: first class, second class and third class. The difference
between the three classes depends on where the force, the fulcrum or the load is.
In a second class lever, the output force is between the fulcrum and the input force.
A lever is a bar that turns on an unmoving point called a fulcrum. When you push or pull
on one end of the bar that pressure is called the force. The object that is lifted on the
other end is called the load.
There are three parts to all levers:
•
Fulcrum - the point at which the lever rotates.
•
Input force (also called the effort) - the force applied to the lever.
•
Output force (also called the load) - the force applied by the lever to
move the load.
There are three types of levers: first class, second class and third class. The difference
between the three classes depends on where the force, the fulcrum or the load is.
In a third class lever, the input force is between the fulcrum and the output force.
Other simple machines can be
found throughout the body
Fingernails act like WEDGES
Your patella acts like a PULLEY
It changes the direction of the force when your
quadriceps muscle pulls on your tibia
Your shoulder acts like a WHEEL AND AXLE when you throw a ball
and your rotator cuff moves your humerus through an arc, but
anatomically it is very different.
Another movement amplifier!