of water can be a little difficult, but could you
lift another person?? The more mass something has, the harder
gravity pulls down on it. But people have learned to 'outsmart'
the force of gravity by using a simple machine such as a lever, which
is a key concept in the seesaw.
Pivot point is the triangle
A seesaw is a great example of
a lever. The fulcrum/pivot point is the part of the lever that
does not move, its in the middle. The resistance, or the
downwards force, is the weight of the person you are trying to lift is
at one end. The work, force applied to the lever, is the person
sitting on the other end of the seesaw.
The force that is applied by pushing down/pushing up on one end of the
seesaw can substitue for the mass on the other end. The longer
the lever, the less force one needs to lift a heavy object.
"The mechanical advantage of
using a long lever to lift a heavy weight is
apparent: much less force is need to lift a heavy object with
a lever if the distance
from the pivot point is large compared to the distance of the
heavy object from the
pivot point." --See Saw Physics Lesson