Answer 1:
Not sure what you are asking - energy exerts a
gravitational field, whether the energy is in its
rest form (i.e. mass) or its kinetic form (what we
normally think of as energy). Gravitational fields
produce a gravitational potential well, in which
something falling into that well picks up kinetic
energy (losing rest energy) as it does so. So, for
example, the space shuttle is ever so slightly
more massive when it is in orbit than when it is
on the ground, because when it is on the ground it
is deeper into the Earth's potential well. The
only way to release the "stored"energy is to fall
into the well. As an example, you may be
familiar with a medieval siege engine called a
trebuchet (TRAY-beu-SHAY), which operates by
having a large weight on the end of a lever arm,
and letting the weight fall swings the lever that
in turn hurls a projectile. The weight falling
into the Earth's potential well releases its
energy that is then transferred via the lever arm
into the missile, which is usually a boulder. If
you saw the cinematic adaptation of The Return of
the King(the third volume of the Lord of the Rings
trilogy),the soldiers on the walls of Minas Tirith
were using war machines to hurl blocks of masonry
at Sauron's armies - those were
trebuchets. It's not possible to suck the
energy out of the Earth's gravitational field such
that the Earth has no gravity, however. Click Here to return to the search form.
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