検索結果- 英語 - 英語
検索内容:
Supplee's paradox
name
(physics)
A
physical
paradox
that
arises
when
considering
the
buoyant
force
exerted
on
a
relativistic
bullet
(or
in
a
submarine)
immersed
in
a
fluid
subject
to
an
ambient
gravitational
field.
If
a
bullet
has
neutral
buoyancy
at
rest
in
a
perfect
fluid
and
is
then
launched
at
relativistic
speed,
observers
at
rest
within
the
fluid
would
conclude
that
the
bullet
should
sink,
since
its
density
will
increase
due
to
the
length
contraction
effect.
On
the
other
hand,
in
the
bullet's
proper
frame
it
is
the
moving
fluid
that
becomes
denser
and
hence
the
bullet
would
float.
Abilene paradox
noun
Ehrenfest paradox
name
(physics)
A
relativistic
paradox
concerning
the
concept
of
Born
rigidity
within
special
relativity,
where
an
ideally
rigid
cylinder
that
is
made
to
rotate
about
its
axis
of
symmetry.
The
radius
R
as
seen
in
the
laboratory
frame
is
always
perpendicular
to
its
motion
and
should
therefore
be
equal
to
its
value
R₀
when
stationary.
However,
the
circumference
should
appear
Lorentz-contracted
to
a
smaller
value
than
at
rest.
This
leads
to
the
contradiction
that
R
=
R₀
and
R
<
R₀.
Loschmidt's paradox
name
Burali-Forti paradox
name
gentle murder paradox
noun
unexpected hanging paradox
noun
A
paradox
about
a
person's
expectations
about
the
timing
of
a
future
event
which
they
are
told
will
occur
at
an
unexpected
time.
It
is
based
on
the
idea
that
a
prisoner,
told
that
he
will
be
hanged
on
a
day
unknown
to
him,
concludes
that
"I
cannot
be
hanged
on
Friday
because
if
I
haven't
been
hanged
by
the
end
of
Thursday
then
it
would
no
longer
be
a
surprise",
and
so
on
backwards
through
the
week.
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