Evening star. [volume] (Washington, D.C.) 1854-1972, 1926-01-13
Inductance and Capacity as Forms oil
Inertia. Part IL.

Fans who have made a study of
mechanics or physics in high school
or college will probably remember
an old statement as regards the con-
servatton of matter and the conser-
walton of energy. Briefly, the first of
these laws states that matter can
neither be created nor destroyed. We
can change material from one form
into another. but we cannot destroy
1T. We may change a large rock into
a large number of small ones, but the
quantity of matter will remain the
same; we may burn coal so that
some of 1t goes up as smoke. another
part goes off as gas while some re-
mains as ashes. but the total amount,
II all the various portions could be
caught and weighed would be the
same as before 1t was burned
TIL esecond one, that has to do with
conservation of energy, can be made
to show that the amount of energy
is always the same but that the form
of energy may change. In lifting a
weight to a height the energy eX-
pended in lifting the weight is chang
ed into energy of position or poten-
tial energy because of the position
to which the weight has been raised
so that It can do the same amount OF
work by virtue of its position as was
expended to put it there. The only
energy lost" Is that expended in
overcoming friction, as is the case
when q system of pulleys Is used to
raise the weight. The energy lost"
through friction is not really lost, but
transformed into heat energy and
made unavailable.
The only factor that causes dis
sipation of energy is actual friction
In the mechanism used to lift the
weight.
Air Compressor L Sed.
Another form of doing work and
changing one form Of energy into
another is that of working an air
compressor to force air or gas into
a chamber under pressure. The air
or gas under pressure can then be
made TO do work by being released
in proper air or gas motor. where
the expansion of the compressed air
or gas against piston reC0nvertS
the energy OF compressed air into
motiOn.
St.ll another form OF convertine
energy of motion into potential ener-
ey is that i'll which force is applied
| to compress Il compression type OF
spring, pull out a tension spring or
, bend a bow, as. for instance. in Il bow
and arrow arrangement. The energy
expended in COMPRISING or extend %
+ ing The springs or the energy eX-
pended in drawing the bow can be
released to drive an object to great
distance or to move mechanical
Contrivance. such as Il spring motor.
The energy stored up in such ar
engagements is always the same us
that expended minus the amount
lost or dissipatei in friction.
Inertia Explained.
The inertia Of a body or mass is
that property which tends to resist
any attempt 10 change its condition
Of rest or motion. You remember the
old textbook statement that If Il
body Is at rest il tends to remain ~
rest and to resist any attempt IL
cause its motion. Likewise. il Il body
Is moving at contsan Mt rate of speed
II tends 10 resist any attempt to
either decrease or increase its speed
II body is at res. force must be
applied TO move il. and, since action
and reaction is equal and opposite
the force applied is opposed by AN
equal force. A considerable force, for