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Turn in your HW. Take out your Guided Notes from last class and leave them on your desk. Tonight’s HW: See Supplemental Chapter 1. Read pgs 1-2. Do #1-6 on pg 8 ( 5 points). Follow the format below!!!Homework Example: Let’s say the question is, “On a nice, sunny day, what color is the sky?”ID# NAME DATE CLASS 1. The color of the sky on a sunny day is blueOR 1. What color is the sky? BlueNOT1. Blue how does this help you??? It doesn’t!**Give enough detail so that you are successful on an open notes quiz!** http://www.youtube.com/watch?v=ajTeseYcimE http://www.youtube.com/watch?v=D9XYKY4Km20
FYI - FROM NOW ON: *If… • - ID# is not on top left hand corner of HW, you will lose 1 point *If… • - Name is not on HW, you will NOT receive credit for your HW
Do Now: #25-26(pg 9 of Supp. Ch. 1.) Please REWRITE the problems/answers (can bullet point) on loose leaf with enough detail that you remember the problem for an open notes quiz. #25 #26 • A cat lies on the floor. • Can you say that NO FORCE acts on the cat? Or, is it correct to say that no net force (in other words, ZERO NET FORCE) acts on the cat? • EXPLAIN your answer (why/ how you answered the way you did etc.) • Consider 2 forces: one having a magnitude of 20N, and the other a magnitude of 12 N. • What is the maximum net force possible for these 2 forces? • What is the minimum net force possible for these 2 forces?
#26 • ANSWER : MAXIMUM resultant occurs when they are parallel, in the same direction • 20N + 12N = 32 N • #25 • MINIMUM resultant occurs when they are in OPPOSITE directions • 20 N – 12 N = 8 N ANSWER: It is correct to say no net force. Both gravity (cat weight) and support force (thanks floor) act on cat. They cancel to zero net force, but there are still forces!
Exit Slips from last class • Take yours back and review with peers… we will go over answers in a minute!
Make any necessary corrections on yours!
FYI - FROM NOW ON: *If… • - ID# is not on top left hand corner of HW, you will lose 1 point *If… • - Name is not on HW, you will NOT receive credit for your HW
An object in mechanical equilibrium is stable, without changes in motion.
Remember from last class… A NET force is needed to change an object’s state of motion. If there is zero net force, then there is zero change in the object’s state of motion Remember from last class… If an object is… • At rest OR • Moving in a straight line at the same speed Then the net force on that object is zero…there is no net force!
Now, your turn… • Please READ sections 2.2 and 2.3 in your Supplemental Ch. 1. (pgs 3, and some of 4) • As you read, make NOTES in the margins / highlight … how do you think / interpret the text? • Complete #14-20 in guided notes • You MAY work with others, talk, etc. • You have 10 minutes to get this done! We will quicklyreview answers as a class. If you have questions, you should ask NOW, during these 10 minutes!
As you read… • What did you NOTE / highlight? • How do you think / interpret the text? • Discuss!
With ASSIGNED lab groups…read pages 4-7 in Supp. Ch 1. and complete up to the stop sign on your Supplemental Ch. 1 Guided Notes Continued Handout. Check in w/teacher at • We will not go over as a class – it is your group’s responsibility to pace accordingly and check in at • Take the time to explain answers, but be EFFICIENT. There can always be a pop quiz on material you are expected to complete! (Today you should AT LEAST complete up to #12 on p. 3) • You will have time to meet with lab groups next class to review/complete today’s handout. Each lab group will present their answers from some problems from Chapter Review (boxes on pg. 3-4).
Exit Slips! • Take an exit slip and SILENTLY write your answers (THREE questions!) • Next class, we will review answers on Powerpoint. When the answer comes up, you will MAKE YOUR CORRECTIONS in a different color(or, circle them, etc…do something to make them stand out to me!) • These are not graded, so it’s ok if you make corrections! • To be turned in when done. These will be returned to you next class.
2.3Support Force think! Suppose you stand on two bathroom scales with your weight evenly distributed between the two scales. What is the reading on each of the scales? What happens when you stand with more of your weight on one foot than the other?
2.3Support Force think! Suppose you stand on two bathroom scales with your weight evenly distributed between the two scales. What is the reading on each of the scales? What happens when you stand with more of your weight on one foot than the other? Answer: In the first case, the reading on each scale is half your weight. In the second case, if you lean more on one scale than the other, more than half your weight will be read on that scale but less than half on the other. The total support force adds up to your weight.
2.5Vectors think! Two sets of swings are shown at right. If the children on the swings are of equal weights, the ropes of which swing are more likely to break?
2.5Vectors think! Two sets of swings are shown at right. If the children on the swings are of equal weights, the ropes of which swing are more likely to break? Answer: The tension is greater in the ropes hanging at an angle. The angled ropes are more likely to break than the vertical ropes.
2.5Vectors think! In your own words, please describe why it is more difficult to do pull-ups with one arm, instead of 2. Include key terms we have used today. You will not be given the answer for this today… Do your best
Next Class We Will… • Pass back Metric Quests and you will have opportunity to ask peers/teacher if you have questions • Popcorn HW Answers #1-6 from Supp. Ch. (p.9) • Meet with lab groups to touch base on Supp. Ch. 1 Guided Notes continued answers (you should work on this individually at home if you did not finish in class today) • Present the Chapter Review Question Boxes from your Supplemental Ch. 1 Guided Notes Continued Handout
