Chapter 11, Lesson 2: May 1 & 2
HW Due
Read & Study 11.1 - 11.3.
Do #1-6, 21 – 24, 26, 33 (p. 165–66)
(13 pts – 1 pt each and 1 pt for 1 graded on correctness)
Tonight’s
HW
Read & Study 11.4 - 11.7 –
Do #7 – 15, 17 – 20 (p. 165-66)
(14 pts – 1 pt each and 1 pt for 1 graded on
correctness)
Don’t forget – test on Ch. 9 & 10 May 7(A) & 8(B)
Finish your study guide by the END of class May
5(A) & 6(B) for +5!
Do Now
Take a clicker…
Take a DO NOW from my desk!
DO NOW: What is the weight of the unknown
box?
0%
0%
100%
0%
0%
0%
0%
0%
0%
A.
B.
C.
D.
E.
F.
G.
H.
I.
4.5 N
60 N
160 N
240 N
540 N
1800 N
4800 N
10,800 N
None of the above
What is the weight
of the unknown
box?
First, let’s check…which object has a larger lever arm?
So…which force has to be larger?
So we know our ‘mystery weight’ is MORE than 120 N
F x 30 cm = 4800 N cm
Divide both sides by 30 cm ….
Force = 160 N
DO NOW: A meter stick is balanced as shown. If a
200 gram mass is placed at the 20 cm mark (30
cm from the turning point), at what mark should
a 500 gram mass be placed so that the system
balances?
10%
81%
0%
5%
5%
0%
0%
A.
B.
C.
D.
E.
F.
G.
8 cm
12 cm
50 cm
62 cm
4000 cm
6000 cm
None of the above
DO NOW: A meter stick is balanced as shown. If a 200 gram
mass is placed at the 20 cm mark (30 cm from the turning
point), at what mark should a 500 gram mass be placed so
that the system balances?
First, let’s check…which object is the bigger force /
weight??
So…which lever arm has to be larger?
So we know our 500g’s LA MUST be smaller than 30 cm
DO NOW: A meter stick is balanced as shown. If a 200 gram mass is
placed at the 20 cm mark (30 cm from the turning point), at
what mark should a 500 gram mass be placed so that the system
balances?
Divide both sides by 500 g ….
LA = 12 cm
BUT WE ARE NOT DONE!
DO NOW: A meter stick is balanced as shown. If a 200 gram mass is
placed at the 20 cm mark (30 cm from the turning point), at
what mark should a 500 gram mass be placed so that the system
balances?
The question asks at what mark should it be placed?
If it’s suspended from 50 cm…
Then 50 cm + 12 cm =
The 62 cm mark!
LAB PRACTICUM
• Return your clickers
• Arrange yourselves in groups of 1 – 5 at desks or lab
benches
• Only items allowed out are a PEN and CALCULATOR…
NOTHING ELSE!
– Must use a calculator that is NOT your phone or iPod
– MAY NOT USE NOTES OR BOOK
– May have a piece of loose leaf, or teacher will give you a
piece of scrap paper.
• Follow all directions on the graded form. When you are
ready to test your set up, call the teacher over.
• When done, review your HW from last night with your
group.
• 10 minutes total to complete – failure to do so = 0/25!
Take out the HW from last night
• Cross off #24
• The next slide will contain the answers for your HW
• Consider it to be like a word back – the answers are
not in order
• Your answer wording might vary slightly…and that’s
OK!
• Check and make corrections with your peers!
• ANSWERS MEAN NOTHING if you don’t know HOW
to get them!
• Ask a teacher for help if needed!!!
• 3 minutes
•
•
•
•
•
•
#1-6
Perpendicular to LA
CG
They are equal
Force changes
velocity; torque
changes rotation
CG extends beyond
area of support,
producing a torque
(due to
gravity)…you fall!
Distance from the
axis/fulcrum to the
force
#21-23, 26, 33
•
•
•
•
•
•
•
•
•
2 kg
Check your
HW!
3m
Answers NOT
in order!
10 Nm
900 Nm each, 0 total
25 Nm
1.5 m
2m
Longer feet = more area of support
Longer handle for prying open;
thicker handle for stubborn screws.
Both provide bigger lever arms
•
•
•
•
•
POST LAB
Timed assessment – you have 10 minutes
Go to test seats - Open notes; NOT open text
Can use a calculator
Phones out and SILENT
EXTRA CREDIT – YOU MUST SHOW WORK for each
Mystery Box NEATLY and LEGIBLY in order to earn
points
– Attach loose leaf if you need more space
• NO TALKING UNTIL TEACHER SAYS ITS OK – if you talk
before you are given permission, you WILL LOSE
POINTS.
• When you are done, turn in post lab and take a copy of
Ch 11 POGIL #2. SILENTLY return to test seat and work
on notes.
POGIL
• Work efficiently – check in at stop signs
• Whatever you do not get done today will be
completed next class (the only HW you have
tonight is from your book).
• We are stopping with 3 minutes left for an exit
• You have a TEST 2 classes from today…. Ensure
that you are working to the best of your ability
and getting the help you need!!!
Exit Slip
Take one, complete, & turn in
NEXT CLASS
• We will wrap up anything from today’s POGIL
– (it is not HW if you don’t finish, but you do have questions from
your book)
• We will review the HW
• You will have the remainder of class to work on your study
guide
• The study guide is due at the end of next class for +5
• Your HW next class will be to prep for the Ch 10 & 11 test