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Physics Lesson 3 Strategies of Studying Physics. Eleanor Roosevelt High School Chin -Sung Lin. Strategies of Studying Physics. Use physics words with precision. Know the concepts behind the formulas. Apply dimensional analysis. Develop problem solving skills.
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Physics Lesson 3Strategies of Studying Physics Eleanor Roosevelt High School Chin-Sung Lin
Strategies of Studying Physics • Use physics words with precision • Know the concepts behind the formulas • Apply dimensional analysis • Develop problem solving skills • Think through the math
Use Physics Words with Precision Definition of Physics Words • Physics words have precise definitions • May be different from their regular English meanings • Engage in “physics talk” • Work • Displacement • Distance • Momentum • Speed • Power • Velocity • Potential • Impulse • Current • Energy • Field • Gravity • Force • Acceleration • Normal
Know the Concepts behind the Formulas Context of Physics Formulas • Physics formulas has conditions attached to them • Fnet = ma • W = Fd • Net force • Any force
Know the Concepts behind the Formulas Context of Physics Formulas • Concepts and principles form the basis of formulas • mghA + ½ mvA2 = mghB + ½ mvB2 • PEA + KEA = PEB + KEB • ETA = ETB • Conservation of Energy
Know the Concepts behind the Formulas Context of Physics Formulas • Engage in the “concept explaining process” • Any forms of teaching, explaining, or writing physics
Know the Concepts behind the Formulas Teaching & Writing Process (Research Results) • Based on a student teaching research:
Know the Concepts behind the Formulas • Data Comparison - Definition Assume: ti is the teaching score of ith student ri is the Regents score of ith student pi is the predicted Regents score of ith student based on ti where i = 1, 2, 3, ……12
12 M = (ri - pi)2 /12 I = 1 Know the Concepts behind the Formulas • Data Comparison - Objective Function Define an objective function M: the root-mean-square (rms) value of the difference between ri and pi
- Know the Concepts behind the Formulas • Regents Scores Prediction • (A Linear Function of Teaching Scores) Results pi = f(ti) = 1.9 ti - 100 or p= f(t) = 1.9 t - 100 M = 15.4 for all students M = 3.5 excluding 3 exceptions
Regents Test Score Prediction I(A Linear Function of Teaching Scores)
Know the Concepts behind the Formulas • Data Comparison - Definition Assume: s1i - ave. test score of 1st mp for ith student s2i - ave. test score of 2nd mp for ith student di - difference btw s2i & s1i for ith student where i = 1, 2, 3, ……12 di = s2i -s1i
Know the Concepts behind the Formulas • Regents Scores Prediction – • (A Linear Function of Teaching Scores and Test Scores) Results pi = f(ti, di) = 1.615 ti + 0.3 di - 74.5 or p= f(t, d) = 1.615 t + 0.3 d - 74.5 M = 13.3 for all students M = 1.9 excluding 3 exceptions
Regents Test Score Prediction II(A Linear Function of Teaching Scores and Test Scores)
Know the Concepts behind the Formulas Teaching & Writing Process (Research Results) • Based on a student teaching research: • Teaching scores is a strong predictor for the Regents test • The trend of the average test score serves as a modifier • The impact of teaching scores is five times stronger than the trend of the average test scores • Teaching (including writing) represents understanding • Teaching (including writing) could strongly improve understanding
Apply Dimensional Analysis Derived Units • Know the symbols/definitions of derived units • Speed (v): m/s • Acceleration (a): m/s2 • Force (F): kg m/s2 (N, newton) • Work (W): kg m2/s2, N m (J, joule) • Power (P): kg m2/s3, N m/s (W, watt) • ………………………………
Apply Dimensional Analysis Dimensional Analysis • Every equation must be balanced dimensionally • Units on both sides of the equation must be identical • d = vt + ½ a t2 • m = (m/s) s + (m/s2) s2
Apply Dimensional Analysis Dimensional Analysis • Example: • If v is velocity, m is mass, a is acceleration, and a = Δv/t and F = ma, find the unit of force (F)
Apply Dimensional Analysis Dimensional Analysis • Example: • If v is velocity, m is mass, a is acceleration, and a = Δv/t and F = ma, find the unit of force (F) • F = m a = mΔv / t • Unit of F = kg m/s/s = kg m/s2
Apply Dimensional Analysis Dimensional Analysis • Example: • If gravitation force (Fg) can be described by the following formula, find the dimension of G • Fg = G m1 m2 / d2
Apply Dimensional Analysis Dimensional Analysis • Example: • If gravitation force (Fg) can be described by the following formula, find the dimension of G • Fg = G m1 m2 / d2 • kg m/s2 = [G] kg kg / m2 • [G] = m3 / kg s2
Apply Dimensional Analysis Dimensional Analysis • Unit Conversion – Use dimensional analysis to do unit conversion • Example: Find how many seconds per day
Apply Dimensional Analysis Dimensional Analysis • Unit Conversion – Use dimensional analysis to do unit conversion • Example: Find how many seconds per day • ? sec 24 hrs 60 min 60 sec 86400 sec • _____ = ______ x _____ x ______ = __________ • 1 day 1 day 1 hr 1 min 1 day
Apply Dimensional Analysis Dimensional Analysis • Unit Conversion – Use dimensional analysis to do unit conversion • Example: Find how many seconds per day • ? sec 24 hrs 60 min 60 sec 86400 sec • _____ = ______ x _____ x ______ = __________ • 1 day 1 day 1 hr 1 min 1 day
Develop Problem Solving Skills Physics Problem Solving • Encompass many physics concepts, principles, formulas, and mathematical disciplines • Problem solving skills: • Analyze problems • Associating physics concepts/principles/formulas • Apply mathematical skills
Develop Problem Solving Skills Physics Problem Solving Steps • Make a sketch • Classify the description • Identify and list all the known & the unknown • Associate with physics concepts, definitions, relationships, formulas, and principles • Form & solve mathematical models
Develop Problem Solving Skills Example • A block is placed on an incline plane with angle . The coefficient of friction between the block and the incline plane is . The acceleration due to gravity is g. Find the acceleration of the block a in terms of g, and
Develop Problem Solving Skills Example
Develop Problem Solving Skills Example
Develop Problem Solving Skills Example
Thinking through the Math Mathematical Models • Math can describe complex physics phenomena and capture the relationship among physics quantities in an elegant and concise way • Fnet = ma • W = Fd • V = IR • Q = It • p = mv • P = w/t
Thinking through the Math Mathematical Models • You have to analyze physics problems and reduce them into mathematical forms. On the other hand, you can apply physics laws in mathematic forms (formulas) to solve physics problems • Math is a powerful tool for understanding those physics phenomena that go against or beyond our common sense