SJI_2020 Year 3 EOY Physics 6091 P3 Student Answers

St. Joseph’s Institution Year 3 Physics (6091) 1 2020 Year 3OP END-OF-YEAR PHYSICS PRACTICAL EXAMINATIONS RUBRICS Question Answer 1(a)(i) Correct precision and unit only. (t0 =2.91 s) 1(a)(ii) Correct precision and unit only. (t1 =1.74 s) 1(b)(i) v0 = 99.0/2.91 = 34.0 cm/s [allow “m/s”] v0 is correctly calculated to the correct s.f. & unit using sf rule 1(b)(ii) v1 = 50.0/1.74 = 28.7 cm/s [allow “m/s”] v1 is correctly calculated (smaller than v0) to the correct s.f. & unit using sf rule 1(c) a = 2 x [(34.0-28.7)/(2.91-1.74)] = 9.1 cm/s2 a is correctly calculated (ecf) to the correct s.f. & unit using sf & dp rule

St. Joseph’s Institution Year 3 Physics (6091) 2 Question Answer 2(e) “h” has correct precision and unit. (h = 4.0 cm) 2(f) (Either) Using the protractor provided, draw a perpendicular line from RR’ (or) measure 2 equal distances from QQ’ to locate the mirror line Ensure the line is longer than the width of the mirror so as to align both sides of the mirror accurately 3(h) This is to ensure that the line drawn over the pin positions is accurate. This affects the accuracy of “y” 3(i) At least 2 of the lines joining P3 and P4 are parallel to each other. 3(j) “y” has correct precision and unit. (y ~ 3.0 cm) 3(l) At least five sets of h & y data. Table heading with quantities with correct units. All values of h & y to 0.1 cm precision. Range of h at least 4.0 cm 3(m) Axes labelled with units and correct orientation. [Allow ecf from wrong unit in table.] Suitable scale, not based on 3, 6, 7 etc with plotted data occupying more than half the graph paper in both directions. All points plotted correctly (points must be ≤ ½ small square from the correct position) Best fit line and fine crosses. Use of a triangle that uses more than half the graph line + 2 (x,y) coordinates of correct precision 3(n) Correct calculation of gradient “k” with correct lowest s.f. (Teacher’s reference value: k = between 0.542 and 0.662) “k” calculated to the correct lowest s.f. (no sf , dp rule here) “c” read directly or calculated correctly from graph or correctly calculated. “c” calculated to the correct lowest s.f. (no sf , dp rule here) 3(o) It is difficult to perfectly align the centre of the closest pin (P4) to the centre of the furthest pin (P2). This affects the accuracy of the value y.