Complete Force & Motion Concept Survey – Post Test Name & SID Discussion of Pre and Post Test results from 2007/8 Why are the performances in the Post tests so BAD ? How can you improve your performance? Better problem solving strategies Identity Setup Execute & Evaluate Later lecture will discuss your Pre and Post Test performance

Identify  Setup  Execute  Evaluate IDENTIFY Identify what the question asking Identify the known and unknown physical quantities (units) SETUP need a good knowledge base (memory + understanding) Visualise the physical situation Diagrams - reference frames / coordination system / origin / directions Write down key concepts, principles, equations, assumptions that may be needed to answer the question EXECUTE Answer to the question from what you know. Numerical questions - solve before calculations - manipulate equations then substitute numbers add comments. EVALUATE CHECK - answer reasonable, assumptions, units, signs, significant figures, look at limiting cases

Questions Force ??? acceleration and velocity

2008 total sample N = % post N = 32 (27.8%) pre N = 4 (3.5%) post N = 31 (27.0%) pre N = 56 (48.7%) post N = 52 (45.2%) pre N = 55 (47.8%) Cat.1Cat.2 Cat total sample N = % post N = 12 (13.3%) pre N = 0 (0%) post N = 43 (47.8%) pre N = 46 (51.1%) post N = 35 (38.9%) pre N = 44 (48.9%) Cat.1Cat.2 Cat.3 Questions correct 4/5 guess

Identify  Setup  Execute  Evaluate m x y

m x y Newton’s 2 nd Law Force and acceleration are in same direction Force and acceleration vary in the same manner

Identify  Setup  Execute  Evaluate m x y Newton’s 2 nd Law Force and acceleration are in same direction Force and acceleration vary in the same manner Incorrect reasoning – force related to velocity in direction and magnitude

Your Pre test Question 12 – Coin tossed in the air – force at its highest point ? Correct answer Force is down and constant (A) 5% Incorrect reasoning Force is zero (D) 86%

y 1 = sin(2  x/ ) y 2 = sin(2  (5-x)/ ) y 1 + y 2 = 6 m