Comments on grading of prelim 1, TAM 203, Fall 2000 Grading rule for question 1: 1a) FBD (3 pts) LMB (3 pts) *(incorrect sign -1pt) General solution (2 pts) initial condition (2 pts) x(t) form (2 pts) get time (3 pts) *(incorrect time -2pts) 1b) correct x(t) form (3 pts) how velocity reverses (4 pts) how far (3 pts) *(calculate time instead of distance -2pts) 1c) FBD (3 pts) *(one incorrect mark -1pt) LMB (3 pts) *(one incorrect sign -1pt if your FBD is right) particular solution (2 pts) get correct B and C (2 pts) correct x(t) form (2 pts) distance (3 pts) *(if answer is right without reasoning 1pt) * There is no extra points for working on homogeneous solution. * IF you only worked on homogeneours solution, the total would be FBD (3 pts) LMB (3 pts) homogenours solution (3 pts) when everything is correct/ Grading rule for question 2: Free Body Diagram: (10 pts) Forgetting/adding force in LMB: -5 Spring and Dashpot Forces: (10 pts) Calculating a force incorrectly: -5 Sign of force inconsistent with FBD: -3 LMB and correct acceleration: (10 pts) Sign of force added inconsistent with FBD: -3 Neglecting mass in acceleration equation: -5 Grading rules for question 3: Free Body Diagram and LMB: (7 pts) Not specifying directions in FBD in some manner: -3 Setting up System in terms of unit vectors and tensions: (8 pts) Setting up System for MATLAB solutions: (5 pts) MATLAB Code: (10 pts) Forgetting to select component from final acceleration vector, or selecting the wrong component: -3 Mixing up indices in array access: -3 Forgetting mass: -5 Small syntax error: -1 If you did not find the tensions, but were COMPLETELY correct in setup and code for finding acceleration given tensions, you got 20 pts (or -10).