EJC 2023 J1 H2 Promo P4 (Sample Report)

©EJC 2023 9749/04/J1H2PROMO/2023 [Turn over EUNOIA JUNIOR COLLEGE JC1 PROMOTIONAL EXAMINATIONS 2023 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 2 3 - REGISTRATION NUMBER PHYSICS Paper 4 Practical 9749/04 15th September 2023 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 14 2 19 Total 33

2 ©EJC 2023 9749/04/J1H2PROMO/2023 1 In this experiment, you will investigate the behaviour of a system in static equilibrium. (a) (i) Determine the mass of one paper clip. mass of one paper clip = ................................ [2] (ii) You are provided with two strings. Connect two mass hangers with the shorter string and place them on both sides of a pulley. The mass hangers should balance each other’s weight and hang in equilibrium. Add paper clips, one by one, to one side as shown in Fig. 1.1 until the pulley starts to rotate. Record the minimum number of paper clips that is required to cause the pulley to rotate. number of paper clips = ........................[1] paper clips mass hangers string pulley retort stand loop Fig 1.1 clamp bench Mass of 10 paper clips = 10.37 10.36 10.37 g2 + = Mass of 1 paper clip = 10.37 1.037 g10 = 1.037 g Average number of paper clips = 66 62 + = 6

3 ©EJC 2023 9749/04/J1H2PROMO/2023 [Turn over (b) Using the longer string, set up the apparatus as shown in Fig. 1.2. Mass m and M are provided by a 50 g mass hanger and a pendulum bob, respectively. Fig 1.2 (i) Adjust the position of m along the string until the angle θ is symmetrical about the vertical axis. Measure and record θ. θ = ................................ [1] (ii) Estimate the percentage uncertainty in your value of θ. percentage uncertainty in θ = ................................ [1] bench stand pulley m M string θ o 1 / θ o 2 / θ o / θ 145 144 145 145o o o 5100% 100%145 3.4% θ θ ∆ ×= × = 3.4%

4 ©EJC 2023 9749/04/J1H2PROMO/2023 (c) M, m and θ are related by the expression 2 cos 2Mm θ = . (i) Calculate the value of M. M = ................................ [1] (ii) Using your values in (a)(ii) and (b)(ii), estimate the maximum value of M. maximum M = …………………………. [1] (iii) Repeat (b)(i) for m = 100 g. θ = ................................ [1] o 2cos 2 50 83 g 1452cos 2 mM θ= = =   83 g max max o uncertainty due to friction in axle of pulley 2cos 2 50 6(1.037) 103 g 1502cos 2 mM θ= + = +=   103 g o 1 / θ o 2 / θ o / θ 103 105 104 104o

5 ©EJC 2023 9749/04/J1H2PROMO/2023 [Turn over (d) It is suggested that 2 (1 cos )mk θ= + where k is a constant. (i) Use your values from (b)(i) and (c)(iii) to determine two values of k. first value of k = …………………………….…………. second value of k = …………………………….…………. [2] (ii) State whether or not the results of your experiment support the suggested relationship. Justify your conclusion by referring to your value in (b)(ii). ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .................................................................................................................................... [2] 2 1 cos mk θ= + 2 42 1 o 50 1.38 10 g1 cos145k = = ×+ 2 42 2 o 100 1.32 10 g1 cos104k = = ×+ 421.38 10 g× 421.32 10 g× 1.38 1.32% difference in 100%1.32 4.5% k −= × = Since percentage difference in k (4.5%) is larger than the percentage uncertainty in θ (3.4%), the results do not support the suggested relationship.

6 ©EJC 2023 9749/04/J1H2PROMO/2023 (e) (i) Suggest a significant source of error in the measurement of θ. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… ………………………………………………………………………………………………. [1] (ii) Suggest an improvement that could be made to address the error identified in (e)(i). You may suggest the use of other apparatus or a different procedure. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… ………………………………………………………………………………………………. [1] [Total: 14 Marks] Accepted sources of error i) Difficult to measure θ accurately, using a protractor held in one’s hand, because of unsteady hands.d ii) Friction present in the ball bearings of the pulley causes the setup to be stable over a range of θ. iii) The hook of the hanger makes it impossible to place the protractor close to the setup. This affects the measurement of θ. iv) Difficult to gauge where the vertical axis is. This makes it difficult to ensure that θ is symmetrical about the vertical axis. v) The hook of the hanger is too thick, making the origin of the angle difficult to judge. Corresponding improvement i) Clamp the protractor with a retort stand, so that it is stable. ii) Lubricate the axle of the pulley. iii) Tie the hanger to a piece of string. iv) Use a plumb line to indicate the vertical axis. v) Suspend the hanger with a piece of string.

7 ©EJC 2023 9749/04/J1H2PROMO/2023 [Turn over BLANK PAGE

8 ©EJC 2023 9749/04/J1H2PROMO/2023 2 In this experiment, you will investigate how the period of oscillation of a bent metal wire varies with the angle between the straight parts of the wire (a) (i) Make a sharp bend in the wire at its centre so that the angle θ between the straight parts of the wire is about 140° as shown in Fig. 2.1. Fig 2.1 (ii) Measure and record θ. θ = ................................ [1] θ wire o 1 / θ o 2 / θ o / θ 140 139 140 140o

9 ©EJC 2023 9749/04/J1H2PROMO/2023 [Turn over (b) (i) Secure the cork using the clamp so that the pin is mounted horizontally. Suspend the wire from the pin so that the arrangement is as shown in Fig. 2.2. Fig 2.2 (ii) Displace the wire from its equilibrium position and release it so that it performs small oscillations in a vertical plane, as shown in Fig. 2.3. Fig 2.3 (iii) Make and record measurements to determine the period T of these oscillations. T = ................................ [1] θ wire pin Let number of oscillations be N N 1 st/ 2 st/ st/ sT/ 20 25.59 25.44 25.52 1.276 1.276