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).