Cambridge A Level Physics 9702 — 2002 May/June Paper 3 · Variant 1

TIME 1 hour 15 minutes INSTRUCTIONS TO CANDIDATES Write your name, Centre number and candidate number in the spaces at the top of this page. Answer the one question. Write your answers in the spaces provided on the question paper. You are expected to record all your observations as soon as these observations are made, and to plan the presentation of the records so that it is not necessary to make a fair copy of them. The working of the answers is to be handed in. Marks are mainly given for a clear record of the observations actually made, for their suitability and accuracy, and for the use made of them. INFORMATION FOR CANDIDATES Additional answer paper and graph paper should be submitted only if it becomes necessary to do so. You are reminded of the need for good English and clear presentation in your answers. CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level PHYSICS 9702/3 PAPER 3 Practical Test MAY/JUNE SESSION 2002 1 hour 15 minutes Candidates answer on the question paper. Additional materials: As specified in Instructions to Supervisors Graph paper This question paper consists of 5 printed pages and 3 blank pages. SPA (CW/CG) S21726/2 © CIE 2002 [Turn over Candidate Centre Number Number Candidate Name FOR EXAMINER’S USE

2 9702/3/M/J/02 For Examiner’s Use 1 In this experiment you will be required to investigate the torsional oscillations of a loaded rod suspended by a spring. (a) The spring has been placed on the cork so that it is positioned in the centre of the rod. Take each piece of plasticine and shape it into a small ball. Carefully push the two balls onto the rod so that their centres are situated at equal distances d from the spring. The value of d initially should be about 10 cm. Clamp the top of the spring using the small blocks of wood provided so that the rod and the balls are suspended horizontally as shown in Fig. 1.1. Fig. 1.1 (b) (i) Measure and record the distance d from the spring to the centre of each ball. (ii) Displace the rod slightly so that it performs torsional oscillations in the horizontal plane as shown in Fig. 1.2. Fig. 1.2 top view clamp blocks of wood spring cork plasticine ball rod d d

3 9702/3/M/J/02 (iii) Make measurements to determine the period T of these oscillations, and record your measurements. (iv) Change the value of d and repeat (i), (ii) and (iii) until you have six sets of readings for T and d where d is in the range 7.0 cm
d
12.0 cm. Include values of T 2 and d 2 in your table of results. (v) Justify the number of significant figures which you have given for d 2. (c) It is suggested that T and d are related by the equation T 2 = where m is the mass of one of the balls of plasticine and I0 and k are constants. (i) Plot a graph of T 2 (y-axis) against d 2 (x-axis). (ii) Determine the gradient and y-intercept of the line of best fit. (iii) Calculate values for k and I0 given that m = 20 g. Include appropriate units with your values. (iv) Use the results of your experiment to find a value for T when there are no balls on the rod. DO NOT WRITE IN THIS SPACE 8 4 2 2 2 0 π π m d         + I For Examiner’s Use [Turn over For Examiner’s Use 8π2m ____ k 4π2I0 ____ k d 2 +

4 9702/3/M/J/02 Measurements and calculations For Examiner’s Use M R A

5 9702/3/M/J/02 Graph grid For Examiner’s Use G

CAMBRIDGE INTERNATIONAL EXAMINATIONS JUNE 2002 GCE Advanced Subsidiary Level MARK SCHEME SYLLABUS/COMPONENT :9702 /3 PHYSICS (PRACTICAL (AS)) #33 University of CAMBRIDGE ¥ Local Examinations Syndicate

Pagetof4 | Mark Scheme Syliabus Paper | AS Level Examinations - June 2002 9702 3 Question 1 - , Measurements and observations Ml M2 M3 M4 MS Readings 6 Write the number of readings as a ringed total by the results table. Check a value for d?. Tick if correct. If incorrect, write in correct value & -1. Check a value for 7. Tick if correct. If incorrect, write in correct value & -1. Ignore smnail rounding errors. Ignore POTE errors (A2 = 0} 6 sets of readings scores 6/6, 5 sets 5/6 etc.. Ifhelp given by supervisor then -1, excessive help then -2. If help is given from the Supervisor then write ‘SR’ in a ring at the top of the front page of the candidate's script. Also, please indicate the type of help given in a written comment by the table of results. More than half measured times > 20 s 1 Repeated readings of time, averaged correctly 1 For each value of d there must be at least two values of 7. If tay not shown, but T (or 7?) calculated from correct tay, then allow. If neither shown, or all raw times are the same, then zero. Quality of results 2 Judged by scatter of plotted points about the line (accept examiner corrections). This mark is only given for 5 or more plots on the grid. Look at trend of plots. Allow five trend plots and one outlier for two marks. Shallow curve gets one mark. Justification of sfin @ 1 Candidate’s answer must relate the number of sf in d to the number of sf in @, Do not accept answers in terms of decimal places. Presentation of results RI Column headings 1 Every column must be headed with a quantity and a correct unit. Allow d/cm, d in cm, d(cm) or a solidus notation occupying two lines. Do not allow d cm, dey, cm (d) or just cm (with no a).

Page2of4 | Mark Scheme | Syllabus |” Paper AS Level Examinations ~ June 2002 9702 3 Consistency of raw readings. 1 All raw readings of a particular quantity must be given to the same degree of precision (e.g. if one value of ¢ is measured to 2 d.p. then all values of should be given to 2 d-p.). All the d values should be given to the nearest millimetre. All the ¢ values should be given to the nearest 0.1 s or 0.01 s. Write “, at the foot of each correct column of raw readings. Ignore columns of average values. Ring any inconsistency noted, write X ¢ at the foot of the column, and -1. Apply to raw values of ¢ and d only. Significant figures in d? (from raw values of d)} 1 If d measured to 2 SF then allow @? to 2 SF or 3 SF but not 1 SF or 4 SF. If d measured to 3 SF then allow d? to 3 SF or 4 SF but not 2 SF or 5 SF. Graphical work Gl G2 G3 Axes. 1 Each axis must be labelled with a correct symbol (or description). Ignore units. Scales must be such that the plotted points occupy at least half the graph grid in both the x and y directions (i.¢. at least 4 x 6 large squares). Do not allow more than 3 large squares between scale markings on an axis. Do not allow an axis with an awkward scale (n/a 3:10, 7:10, 8:10 etc.) Plotting of points. 1 Count the number of plots on the grid and write this as a ringed total on the grid. Do not allow plots which are in the margin area. All observations must be plotted. Check one suspect plot. Circle this plot. Tick if correct. If incorrect, mark the correct position with a smal} cross and use an arrow to indicate where the plot should have been, and -1. Allow errors up to and including half a small square. Line of best fit. Only expect to see a straight line through a linear trend. A smooth curve drawn through a curved trend is allowable for this mark. This mark can only be awarded for 5 or more plots on the grid. There must be a reasonable balance of points about the line which has been drawn. Do not allow a line which is greater than half a small square thickness.

Page3of4 | Mark Scheme Syllabus | Paper { AS Level Examinations — June 2002 9702 3 G4 Measurement of gradient. , 1 Ignore any units given with the value. Ignore POTE errors. Hypotenuse of A must be at least haff the !ength of the drawn line. Check the read-offs on the x and y axes. These must be within half a small square. If the calculated or quoted lengths for Ax or Ay are inaccurate by more than one small square then zero. Ax/Ay gets zero. Values taken for the table which are on the tine within half a small square are acceptable. A drawn curve will lose this mark. G5 ___y-intercept 1 Check the read-off. Must be accurate to half a small square. Allow the value to be calculated using y = mx + c and a point on the line. A drawn curve will lose this mark. Analysis Al Gradient equated with 8x?m/k (may be implied from working) 1 A2 Value of & (= 1580/gradient value, or 1.58/gradient (using kg)) 1 Circle mass value when checking. POTE errors will lose this mark. A3 Intercept equated with 4n?/,/k (may be implied from working) 1 Ad Value of £, 1 Correct substitution and method of working. A5 — Valid unit of k(N m, kg m’s? or g cm? s?) OR valid unit of /, (kg m’ or gem’) 4 The unit must be consistent with the values which are used. A6 = No balls, T= Vintercept or by calculation using J, and & 1 Ignore sf. Ignore unit. 25 marks in total

Page4of4 | Mark Scheme Syllabus Paper | AS Level Examinations — June 2002 9702 3 Special cases $1 82 83 S4 ss S6 N.B. No raw times /, no record of number of osc; M1, -1; M2 = M3 = 0; R2 =0. Frequency used instead of period (i.e. has calculated n/t), M1, -1; M4=0, If drawn curve then G4 = GS = 0. Raw times ¢ used instead of period 7 (i.e. has calculated ¢2 not 7?); MI, -1 and ecf. Has reversed axes (i.e. plotted @? vs 77}; A2 = A4=0 {unless correct algebraic rearrangement of eqn) Has plotted the wrong graph (e.g. 7? vs d, J vs a? or T vs d etc.); G4 = G5 = 0 (if drawn curve). A2 = A4 = 0. Something obviously wrong (e.g. all times more or less the same, no trend etc.) Mt, -2. POTE error will result in AZ = 0 only Allow A2 and A4 if calculated by substitution provided two points on the line have been used.