Physics 3 – Augo 23, 2016 Do Now: P3 Challenge – (on slips of paper) Add these two vectors analytically and report their sum as a magnitude and angle. A = 45 N at 15o B = 160 N at 145o Hand in Safety Contracts.

Objectives/Agenda Objective: 1 D motion and Error analysis Agenda: Review IB information about 1.1, 1.2, and 2.1 (1D) Review list of specific concepts and skills for Unit 1 Self ratings to determine which to clarify or practice Practice the needed concepts and skills for Unit 1 Assignment: Prepare for Unit 1 Mastery Quizzes on Friday

Skills and Concepts: Where are you? Refer to the IB Objectives List Assess where you are with each objective: 1 – Got it, know about it, know how to do problems, could write my own problems 2 – Pretty sure I remember, know where to find formula on data packet, could use a refresher 3 – Need to review, never did quite get that, don’t remember 4 – Greek, never did it,

Review as needed Teacher reteach mini- lesson Classmate clarifications Teacher created problems to solve (pop quiz) to verify proficiency (boost grade) Student created problems to cross challenge Selection of textbook problems for practice Revisit last year’s materials Record summary statements or recommendations for these kinds of problems Create a concept map Other ideas?

Topics Reviewed Aug 25 1) Adding two vectors to find a resultant magnitude and direction (P3 question) Resolve all vectors into x and y components (Ax = A cos θ, Ay = A sin θ) Add all x components to find resultant x component, Rx Add all y components to find resultant y component, Ry Convert resultant components into magnitude and direction. 𝑅 𝑥 2 + 𝑅 𝑦 2 and 𝑡𝑎𝑛 −1 ( 𝑅 𝑦 𝑅 𝑥 ) , (add 180o if Rx is negative.) Ans: 136 N at 130o

Topics Reviewed Aug 25 2) Plane dropping a payload of supplies to help refugees projectile motion problem. A plane is flying at 125 m/s at an altitude of 30 km. A) How far from the refugees, horizontally, should it let its doors open? B) With what speed does it hit the ground? (Assume negl. air resistance) Hints: Treat the two dimensions separately. X direction motion is constant velocity (ax = 0 m/s2). Y direction motion is freefall with ay =-9.81 m/s2 and uy = 0 m/s. Ans: a) 9.8 km b) 777 m/s

Topics Reviewed Aug 25 Police car accelerated motion vs speeder constant motion competitive motion kind of problem. A police car at rest, passed by a speeder traveling at a constant 110. km/h takes off in hoot pursuit. The police officer catches up to the speeder in 700. m, maintaining a constant acceleration. A) How long (time) did it take to catch to speeder? B) How fast is the policeman going when he overtakes the speeder? Ans: A) 22.9 s B) 61.1 m/s

Typical Physics Problem Solving Assess the physical situation, event or problem. (Read the problem.) Identify what kinds of quantities are relevant. (List symbol for each variable and provide their measurement if possible.) Draw a picture and/or diagram to model the problem. (Shows relationships between objects, labels distances. Perhaps a before/after pairing, or progress in time. Free body diagrams are often drawn next to a drawing. Determine mathematical relationships between variables involved. (Construct from theory or find relevant Equation.) Solve problem (Do the algebra.) Do any needed Unit Conversions (Bring meaning to the answer.) Perform Error Analysis. (How well do you know the answer?)

Today’s Assignment Continue reviewing 1.1, 1.2, and 2.1 (1 D) Prepare for Mastery quizzes for 1.1, 1.2, .1.3 and 2.1 on Friday, Aug 26 Mastery quizzes are worth 10 points and will be two multiple choice questions with 8 points of problems. (Usually one or two problems). IB materials will be integrated as much as possible. May retake mastery quizzes as needed to reach 8/10 proficiency level.