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Forces can be divided into those that
act by direct contact, such as when you push on a door
to open it, and those that that act at a distance, where
there is no apparent physical contact between the
objects. Gravity and magnetism are examples of forces at
a distance. It is difficult to explain how such a force
is possible.
Questions you may have include:
Different forces at a distance
A force is defined as a push or pull.
Typically, forces involve physical contact, such as
pushing on a door. When you pull a wagon, you are
actually pushing on the handle. The only time true
pulling works is when the force acts at a distance, such
as when gravity pulls you toward the Earth.
There is actually a question whether
there is such a thing as direct physical contact. Do the
atoms or molecules of one material actually touch the
atoms of another, or is there a microscopic separation?
To avoid this question, let's define a force at a
distance as one that acts at distances greater than at
the atomic level.
Forces that act at a distance include
some common physics forces. There may be such forces
that we don't know about, including psychic forces.
Common forces in physics that act at a
distance include gravity, static electricity and
magnetism.
There are also forces that we don't
normally observe, since they are so small. These are
molecular attraction and the nuclear forces that hold
the atom together. We won't consider those forces here.
There probably are other such forces
that we don't even know about. In the Star Trek
television and movie series, they often used a "tractor
beam" to pull other space vehicles to the Starship
Enterprise. We don't know if such a beam really exists.
There is a theory of the existance of an
anti-gravity force that actually pushes matter apart. It
is used to explain the rate of expansion of the
Universe.
Some people believe there are psychic or
mental forces that can act at a distance to move objects
or cause other people to do things. It has never been
proven that such forces exist, although it would be fun
to have such power if it did exist.
Push or pull
Most of the forces that act at a
distance are pulling forces, such as the pull of gravity
or the attraction of molecules to each other. Static
electrical and magnetic forces have both push and pull
capabilities. For example, similar magnetic poles push
away from each other.
Now, it only seems natural that if a
moving object smashes into another object, it will cause
the second object to move in the same direction. How can
something push or pull another object, causing it to
move, when they are a distance apart?
The big mystery is how do these forces
work? What causes them to push or pull?
If you study magnets, you can
demonstrate the magnetic field or lines of force. But
what do these lines of force do? Are there tiny little
particles flying from one end of a magnet to another,
such that it pushes against a similar or pole sucks in
an opposite magnetic pole?
There has never been a truly
satisfactory explanation of how forces at a distance
work. Maybe this could be a project for you to try to
make a discovery or establish a theory to explain it.
There are forces what act at a distance,
pushing objects away or drawing them towards each other.
There really isn't a good explanation of how and why
these forces work. |
