EJC 2021 J1 H2 Promo P4 Sample

©EJC 2021 9749/04/J1H2PROMO/2021 [Turn over EUNOIA JUNIOR COLLEGE JC1 PROMOTIONAL EXAMINATIONS 2021 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 2 1 - REGISTRATION NUMBER PHYSICS Paper 4 Practical 9749/04 September 2021 1 hour 30 minutes Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. Answer all questions. Write your answers in the spaces provided on the question paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. Give details of the practical shift and laboratory, where appropriate, in the boxes provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 11 printed pages and 1 blank page. Shift Laboratory For Examiner’s Use 1 12 2 21 Total 33

2 ©EJC 2021 9749/04/J1H2PROMO/2021 1 In this experiment, you will investigate the motion of a marble along an incline. (a) Draw a 45° line in the lower left corner of the graph paper. (b) Secure the graph paper to the wooden board using adhesive putty. Incline the wooden board at an angle θ of about 10°. Use additional adhesive putty to secure the position of the wooden board on the benchtop. Keep the wooden board at the same angle of incline throughout the experiment, as shown in Fig. 1.1. Without using a protractor, determine the angle θ in your set up. Present your method clearly. You may wish to include a diagram. θ = …………………………………. [2] Fig. 1.1 45° 10° side view benchtop 10° wooden board stack of three wooden blocks graph paper side view benchtop wooden board 3.1 cm 17.6 cm • Clear method; measurements of lengths leading to correct use of trigonometry functions • Value of θ within range with appropriate unit • Accept 2 – 3 s.f. 10°

3 ©EJC 2021 9749/04/J1H2PROMO/2021 [Turn over (c) Fold the cardboard to form a track that has a V-shape cross-section. Mark the cardboard track at distances d of 30 mm and 120 mm from one end as shown in Fig. 1.2. (d) Support the unmarked end of the track at about 7 cm above the benchtop using the retort stand, boss and clamp. Position the marked end of the track on the graph paper such that the axis of the track is aligned to the 45° line, as shown in Fig. 1.3. Where appropriate, use adhesive putty to secure surfaces that slip. 0] Fig. 1.2 d 45° 10° 7 cm Fig. 1.3 top view 45° cardboard track y

4 ©EJC 2021 9749/04/J1H2PROMO/2021 (e) A marble released from rest on the track should roll smoothly onto the inclined wooden board. (i) Release a marble from rest at the d = 120 mm mark. Measure and record the maximum distance up along the incline y that the marble travels. y = …………………………………. [1] (ii) Estimate the percentage uncertainty of y. percentage uncertainty of y = …………………………………. [1] (iii) Repeat (e)(i) using d = 30 mm. second value of y = …………………………………. [1] (f) It is suggested that the relationship between y and d is y = kd where k is a constant. (i) Using your data, calculate two values of k. first value of k = …………………………………. second value of k = …………………………………. [1] 1 cmy/ 2 cmy/ 2 cmy/ cmy/ 2.1 2.2 2.0 2.1 2.1 cm 07100 100 3321 y. % %%y. ∆ ×= ×= 33% 1 cmy/ 2 cmy/ 2 cmy/ cmy/ 1.1 1.1 1.1 1.1 1.1 cm 1 1 2 2 21 0 17512 11 0 36030 y .k. d y .k. d. = = = = = = 0.175 0.360 • Value of y to the correct precision (0.1 cm or 1 mm) and recorded with an appropriate unit. • Averaging of at least 2 measurements • Absolute uncertainty must be in the range of 5 mm to 20 mm. • Correct calculation. • Final answer to 2 s.f. • Value of y to the correct precision (0.1 cm or 1 mm) and recorded with an appropriate unit. • Averaging of at least 2 measurements • Correct calculation to check proportionality constant k • k given to 2 or 3 s.f. • k should be dimensionless as it is a ratio of length/length – the units for numerator and denominated should be converted to the same

5 ©EJC 2021 9749/04/J1H2PROMO/2021 [Turn over (ii) Explain whether your results support the suggested relationship. [2] (g) (i) Suggest one significant source of error in this experiment. [1] (ii) Suggest an improvement that could be made to this experiment to address the error identified in (g)(i). You may suggest the use of other apparatus or a different procedure. [1] (h) State and explain the changes, if any, to the value of k if the incline of the wooden board is made steeper. [2] [Total: 12] percentage difference in 0 360 0 175 1000 175 110 k .. %. % −= × = percentage difference in k of 110% exceeds the percentage uncertainty of y at 33% results do not support suggested relationship • Percentage difference in the two k values calculated correctly and given to 2 s.f. • Divide by smaller value of k • Correct conclusion given with reasoning Relevant points can include: • Two sets of readings insufficient to draw valid conclusion. • Marble was moving too fast so was difficult to determine the maximum height it reached, affected measurement of y. Wrong to say marble does not stay at max position for a long time or a short time. The marble does not stay at rest for any duration of time, there is still velocity (and KE) “horizontally” and the velocity component along the slope is 0 only instantaneously (and not for a duration no matter how short). Relevant points can include: (i) Take more variations of d and plot a graph. (ii) Position a video camera in front of the experimental set up and record the motion of the marble while it is in motion. Analyse the video and by playing back using slow motion / analyse frame by frame to determine the maximum height y the marble could travel up the board. (iii) Do trials and place an object (eg eraser) as a marker on the graph paper to help identify the maximum height y more accurately. Failure to provide and describe correctly a source of error in (g)(i) will see no marks given for this item. The gradient of the graph would be less steep By conservation of energy, initial amount of GPE of marble remains constant; marble will moves to a