O
The
main
idea
of
this
chapter
is
quite
simple
:
Horizontal
and
vertical
motion
are
____________________
.
A
ball
thrown
horizontally
continues
to
move
with
the
same
speed
in
the
____________________
direction
,
even
as
it
falls
with
an
increasing
speed
in
the
____________________
direction
.
The
____________________
of
a
vector
are
the
key
to
understanding
the
independence
of
horizontal
and
vertical
motions
.
Of
all
the
mathematical
tools
used
in
this
book
,
none
is
more
important
than
the
____________________
.
In
fact
,
vectors
are
indispensable
in
describing
many
of
the
key
quantities
in
physics
,
like
____________________
,
____________________
,
and
____________________
.
Sometimes
a
scalar
isn't
enough
to
adequately
describe
a
physical
quantity
.
There
are
many
cases
where
a
____________________
is
needed
as
well
.
A
vector
is
a
quantity
that
is
specified
by
both
a
____________________
and
a
____________________
.
The
length
of
a
vector
is
referred
to
as
its
____________________
.
When
we
indicate
a
vector
on
a
diagram
or
a
sketch
,
we
draw
an
____________________
.
It
is
common
in
handwritten
material
to
draw
a
____________________
____________________
over
the
vector's
symbol
,
which
is
very
similar
to
the
way
vectors
are
represented
in
this
text
.
