1. § Today,
we
will
• Conduct
an
Inves4ga4on
• Take
some
notes
• Write
a
short
reflec4on
about
what
we
learned
§ Please
Do
Now:
• get
your
lab
notebook
• get
out
something
to
write
with
Good
Morning!

2. § How
does
ini*al
velocity
affect
the
*me
it
takes
a
horizontally-­‐
launched
projec*le
to
reach
the
ground?
§ Take
a
few
moments
and
read
pg
174
–
175
in
your
text.
As
you
read,
be
thinking
about:
• what
materials
will
you
be
using
• how
the
lab
will
help
you
answer
the
ques4on
• what
your
hypothesis
will
be
Today s
Investigation

3. § Turn
to
the
first
clean
page
in
your
lab
notebook
and
4tle
it,
Chpt
2.
Sec
4
-­‐
Projec4le
Mo4on,
part
1
• Don t
forget
to
make
an
entry
in
your
table
of
contents
§ Copy
the
ques4on
down
at
the
top
of
your
new
page
How
does
ini*al
velocity
affect
the
*me
it
takes
a
horizontally-­‐
launched
projec*le
to
reach
the
ground?

4. § Form
a
hypothesis
that
addresses
the
lab
ques4on.
• remember:
a
hypothesis
is
an
if then
statement
–
and
if
you re
feeling
par4cularly
smart
today,
add
a
because
statement
aSer
the
then
Projectile
Motion,
Part
1

5. § We re
going
to
split
the
lab
into
two
parts.
Your
group
will
have
20
minutes
to
complete
Part
A
of
the
lab
(#1
–
4)
Time
for
the
Lab!

6. § We’ll
get
back
to
the
lab
before
the
end
of
the
period
–
so
leave
your
lab
notebook
out
and
OPEN
§ For
now,
get
out
your
spiral
for
notes
and
a
clean
sheet
of
notebook
paper
for
your
predictions/reAlection
Time
for
Notes

7. It s
as
easy
as
rolling
off
a
cliff…

8. § If
this
red
ball
had
a
net
force
to
the
right
applied
to
it
and
rolled
off
the
cliff
at
a
constant
speed,
what
would
its
path
look
like?
Make
a
Prediction

9. Predict
A B C
Which
path
will
the
ball
follow?

10. § Determine
which
path
you
believe
the
ball
will
follow
AND
WHY.
Write
your
predic4on
on
a
clean
sheet
of
paper
–
we
will
be
adding
to
this
at
the
end
of
this
lesson,
so
keep
it
neat!
J
Prediction

11. A B C
A
few
years
ago,
researchers
went
to
elementary,
middle,
and
high
schools
as
well
as
universities
and
showed
students
this
image
and
asked
them,
Ignoring
air
resistance,
which
of
the
following
correctly
shows
what
an
object
would
do
if
it
rolled
off
a
cliff?

12. § The
breakdown
of
answers
they
got
was
almost
exactly
the
same
at
all
ages.
§ About
60%
said
number
1
was
correct.
The
object
will
stop
in
midair,
and
then
start
to
fall
straight
down.
because
some
people
referred
to
the
coyote
in
cartoons,
the
researchers
called
it
the
Wile
E.
Coyote
Effect.
§ About
25%
said
number
2
was
correct.
The
object
will
move
forward
at
first,
but
will
eventually
just
fall
straight
down.
§ About
15%
answered
number
3.
The
object
will
con4nue
to
move
forwards
the
en4re
4me
it
is
falling.
The
Results

13. § I m
not
going
to
tell
you.
We ll
revisit
the
ques4on
at
the
end
of
these
notes.
J
So
What s
the
Correct
Answer?

14. § Both
coins
fall
the
same
amount
ver4cally
in
the
same
amount
of
4me.
§ The
projected
coin
also
moved
to
the
right;
but
it
fell
downward
at
exactly
the
same
rate
as
the
dropped
coin.
Observations
from
the
lab
In
your
notes,
sketch
what
the
motion
of
these
two
coins
must
have
looked
like

15. § As
we
saw
with
the
coin
launcher,
both
coins
–
the
one
that
fell
straight
down
and
the
one
that
was
flung
out
horizontally
-­‐
hit
the
ground
at
the
same
4me.
§ So
what
effect
did
horizontal
velocity
have
on
the
4me
it
took
(the
downward
mo4on)
the
coin
to
hit
the
ground?
§ The
best
conclusion
we
can
make
from
this
is
that
the
horizontal
mo4on
of
the
coin
does
not
affect
downward
mo4on
of
the
coin.
Observations
from
the
Lab

16. § Intui4on
will
tell
you
that
the
horizontally
launched
object
will
hang
in
the
air.
§ But…
• YOUR
INTUITION
(at
least
in
this
case)
IS
WRONG!
§ Here s
a
video
§ Here’s
another
video
Observations
from
the
lab

17. The
4tle
of
this
slide
says
it
all:
horizontal
and
ver4cal
mo4on
are
independent
of
each
other
–
even
when
they
are
happening
at
the
same
4me!
So…let s
get
back
to
the
ques4on:
Horizontal
and
Vertical
Motion
Don t
Know
Each
Other
Exist!

18. § It
Doesn t!
§ What
is
the
only
factor
(besides
air
resistance,
which
we
are
ignoring)
that
DOES
affect
the
*me
it
takes
a
horizontally-­‐launched
projec*le
to
reach
the
ground?
§ How
high
off
the
ground
the
object
is.
How
does
initial
velocity
affect
the
time
it
takes
a
horizontally-­‐
launched
projectile
to
reach
the
ground?

19. Revisit
Our
Thinking
A B C
Which
path
will
the
ball
follow?

20. 1.
If
a
bullet
is
fired
horizontally
from
a
gun
at
the
same
instant
a
bullet
is
dropped
from
gun
barrel
height,
which
bullet
hits
the
ground
first?
Explain
your
answer
in
terms
of
horizontal
and
ver*cal
velocity,
and
gravity
Reflection
2.
Sketch
the
drawing
on
the
right.
Explain
the
significance
of
the
coins
being
at
the
same
height
at
each
instance
AND
the
significance
of
the
increasing
distances
between
the
“strobe
photo.”
ADV:
if
the
table
is
5m
high,
how
long
are
the
coins
in
the
air?

21. § The
ver4cal
posi4on
of
a
projec4le
constantly
changes,
though.
• Why?
• The
constant
force
of
gravity.
§ As
the
projec4le
rises,
it
slows
down.
As
it
falls,
it
speeds
up.
§ The
change
in
velocity
is
ALWAYS
9.8
m/s
every
second.
(9.8
m/s2)
Motion
of
Every
Object

22. § Any
projec4le
travels
horizontally
and
ver4cally.
§ Ignoring
air
resistance,
the
horizontal
velocity
remains
the
same
• REMEMBER:
force
doesn’t
run
out
and
the
law
of
iner4a
says
objects
in
mo4on
remain
in
mo4on
at
the
same
speed
and
direc4on
unless
a
net
force
is
applied.
Motion
of
Every
Object

23. § To
keep
the
math
super
simple,
let s
round
the
change
in
velocity
to
10
m/s2
§ If
a
projec4le
is
thrown
straight
up
at
40
m/
s,
its
velocity
will
decrease
by
10
m/s
every
second.
§ At
the
top
of
its
path,
its
velocity
is
0
m/s…
• but
immediately,
the
object
begins
to
fall
back
to
earth
where
its
velocity
will
increase
by
10
m/s
every
second.
Motion
of
Every
Object