2020 EJC J2 H3 Prelim QP

©EJC 2020 9814/J2H3 Preliminary Examinations/2020 [Turn over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2020 General Certificate of Education Advanced Level Higher 3 CANDIDATE NAME CIVICS GROUP 1 9 - REGISTRATION NUMBER PHYSICS Paper 1 9814/01 21 September 2020 3 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use paper clips, highlighters, glue or correction fluid. The use of an approved scientific calculator is expected where appropriate. Section A Answer all questions. You are advised to spend about 1 hour and 50 minutes on Section A. Section B Answer two questions only. You are advised to spend about 35 minutes on each question in Section B. 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 37 printed pages and 3 blank page. For Examiner’s Use Section A 1 7 2 11 3 9 4 4 5 10 6 19 Section B 7 20 8 20 9 20 s.f. c.f. Total 100

2 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 Data speed of light in free space, c = 3.00  108 m s–1 permeability of free space, μo = 4π  10–7 H m–1 permittivity of free space, ε o = 8.85  10–12 F m–1 (1/(36 π))  10–9 F m–1 elementary charge, e = 1.60  10–19 C the Planck constant, h = 6.63  10–34 J s unified atomic mass constant, u = 1.66  10–27 kg rest mass of electron, me = 9.11  10–31 kg rest mass of proton, mp = 1.67  10–27 kg molar gas constant, R = 8.31 J K–1 mol–1 the Avogadro constant, NA = 6.02  1023 mol–1 the Boltzmann constant, k = 1.38  10–23 J K–1 gravitational constant, G = 6.67  10–11 N m2 kg–2 acceleration of free fall, g = 9.81 m s–2

3 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 [Turn over Formulae uniformly accelerated motion, s = ut + ½at2 v2 = u2 + 2as moment of inertia of rod through one end I = ML21 3 moment of inertia of hollow cylinder through axis I = M r r2 2 1 2 1 ( )2  moment of inertia of solid sphere through centre I = MR22 5 moment of inertia of hollow sphere through centre I = MR22 3 work done on/by a gas, W = p V hydrostatic pressure, p = ρgh gravitational potential,  = Gm r Kepler’s third law of planetary motion T2 = a GM 2 34 temperature, T/K = T / oC + 273.15 pressure of an ideal gas, p = 21 3 NmcV mean translational kinetic energy of an ideal gas molecule E = 3 2kT displacement of particle in s.h.m. x = xo sin ωt velocity of particle in s.h.m. v = vo cos ωt = 22 xxo  electric current, I = Anvq resistors in series, R = R1 + R2 + … resistors in parallel, 1/R = 1/R1 + 1/R2 + … capacitors in series 1/C = 1/C1 + 1/C2 + … capacitors in parallel C = C1 + C2 + …

4 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 energy in a capacitor U = CV21 2 electric potential, V = 4 o Q r electric field strength due to a long straight wire E = or  2 electric field strength due to a large sheet E = o  2 alternating current/voltage, x = xo sin ωt magnetic flux density due to a long straight wire B = 2 o d   I magnetic flux density due to a flat circular coil B = 2 oN r  I magnetic flux density due to a long solenoid B = on I energy in an inductor U = L 21 2 I RL series circuits 𝜏 = L R RLC series circuits (underdamped) ω = R LC L 2 2 1 4 radioactive decay, x = xo exp (–t) decay constant λ = 1 2 ln 2 t

5 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 [Turn over Please turn over for Question 1

6 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 Section A Answer all questions in this section. You are advised to spend about 1 hour 50 minutes on this section. 1 Fig. 1.1 shows the radar screen on battleship A. Battleship A is always at the origin of the radar screen and the concentric rings represent distances of 10 km, 20 km and 30 km from the battleship A. At 12 p.m., another battleship B is detected on the screen at position B1 with a bearing of 060° from battleship A. At 1 p.m., battleship B is found to be at B2 with a bearing of 100° from battleship A. Fig. 1.1 Assuming that both ships are travelling with the constant velocities, determine (a) the speed of battleship B relative to the battleship A. speed = ………………………. m s-1 [2]

7 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 [Turn over (b) the time (to nearest minutes) when both battleships are closest to one another. time = ..……… : ………. p.m. [3] (c) The bearings and the speed in which a torpedo should be fired relative to battleship A at 1 pm for it to hit battleship B at the time in (b). bearing = ………………… ° [1] speed = ………………… m s-1 [1] [Total: 7]

8 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 2 (a) (i) Show from first principles, that the moment of inertia of a uniform solid sphere with radius R through its centre is given by CM MR 22 5I [3]

9 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 [Turn over (ii) A solid sphere of mass M and radius R is being attached to a massless string of length L and hung at a pivot P as shown in Fig. 2.1. Fig. 2.1 Using your answer in (a)(i), determine the moment of inertia of the solid sphere about the pivot, I. [2]

10 ©EJC 2020 9814/J2H3 Preliminary Examinations/2020 A physical pendulum is any real pendulum, using a body of finite size, as contrasted to the idealized model of the simple pendulum with all the mass concentrated at a single point. An example of a physical pendulum is shown in Fig. 2.1. In the equilibrium position, the centre of mass of the sphere is directly below the pivot. Fig. 2.2 When the physical pendulum is being displaced from the equilibrium by a small angle θ as shown in Fig. 2.2, (b) (i) Write down an expression of the torque produced by the weight of the pendulum. Taking clockwise direction as negative. [1] (ii) Using Newton’s second law for rotation, show that the angular acceleration, 𝛼 of the physical pendulum can be expressed as g(L R ) R L LR          2 2 sin7 25 [2]