NYJC 2023 H2 Physics 9749 P2

NYJC 2023 9749/02/J2Prelim/23 [Turn over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS TUTOR’S NAME CENTRE NUMBER S INDEX NUMBER PHYSICS 9749/02 Paper 2 Structured Questions 14 September 2023 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class, Centre number and index 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 a HB pencil for any diagrams, graphs. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Answer all questions. 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. For Examiner’s Use 1 / 8 2 / 9 3 / 8 4 / 7 5 / 8 6 / 8 7 / 10 8 / 22 Total / 80 This document consists of 20 printed pages.

2 NYJC 2023 9749/02/J2Prelim/23 Data speed of light in free space c = 3.00 × 108 m s−1 permeability of free space  = 4 × 10−7 H m−1 permittivity of free space  = 8.85 × 10−12 F m−1 (1 / (36)) × 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 Formulae uniformly accelerated motion 21 2s ut at=+ 22 2v u as=+ work done on / by a gas W p V= hydrostatic pressure p gh= gravitational potential /Gm r =− temperature / K / C 273.15TT =  + pressure of an ideal gas 21 3 Nmpc V=   mean translational kinetic energy of an ideal molecule 3 2E kT= displacement of particle in s.h.m. 0 sinx x t = velocity of particle in s.h.m. 0 cosv v t = 22 0xx=  − electric current =I Anvq resistors in series 12 . . .R R R= + + resistors in parallel 121/ 1/ 1/ . . .R R R= + + electric potential 04 QV r= alternating current/voltage 0 sinx x t = magnetic flux density due to a long straight wire  = 0 2 IB d magnetic flux density due to a flat circular coil = 0 2 NIB r magnetic flux density due to a long solenoid = 0B nI radioactive decay 0 exp( )x x t =− decay constant 1 2 ln2 t =

3 NYJC 2023 9749/02/J2Prelim/23 [Turn over 1 Fig. 1.1 shows the variation of velocity v with time t for a fuel-propelled model rocket travelling upwards. Fig. 1.1 (a) (i) Define acceleration. [1] (ii) State the time interval when the rocket has the greatest acceleration. between t = s to t = s [1] (iii) Explain why the acceleration of the rocket increases between t = 0 to t = 5.0 s. [1] (b) (i) Suggest a reason for the abrupt change in the motion of the rocket at t = 5.0 s. [1] (ii) Explain how it can be deduced from Fig. 1.1 that air resistance has a negligible effect on the motion of the rocket. [2] t / s

4 NYJC 2023 9749/02/J2Prelim/23 (c) Use Fig. 1.1 to determine the maximum height reached by the rocket. height = m [2] [Total: 8] 2 (a) State the principle of moments. [1] (b) Fig. 2.1 shows part of a cable -stayed bridge. Each section of the bridge is supported by eight equally spaced cables that pass through a central supporting pillar. Fig. 2.1 (not to scale) The cables are at an angle of 50° to the horizontal and the maximum tension allowed in each cable is 7.8 × 105 N. (i) The mass of the roadway in this section is 350 tonnes (1 tonne = 1000 kg). Calculate the maximum mass of traffic that is allowed on this section of the roadway. mass = kg [2] pillar cables section of bridge roadway x 50°

5 NYJC 2023 9749/02/J2Prelim/23 [Turn over cable 30 m T (ii) Suggest a reason why the maximum tension allowed in each cable is well below the breaking tension. [1] (c) Fig. 2.2 shows a suspension bridge. The cables of the bridge are anchored into large free-standing anchor blocks of concrete. Fig. 2.2 The anchor block on the right is shown on a larger scale in Fig. 2.3 . It has a length of 30.0 m and its cross-section and density are uniform. Fig. 2.3 This block is standing on the ground. The maximum force which the cables could exert on this block is 5.50 × 108 N for a particular bridge. This force acts in the direction shown so that its line of action is 26.0 m from the point about which the block might possibly rotate. (i) Calculate the minimum mass of the block needed to prevent rotation, when the force exerted by the cable has its maximum value. minimum mass = kg [2]

6 NYJC 2023 9749/02/J2Prelim/23 (ii) Draw on Fig . 2.4 the two other forces acting on the block under normal operating conditions (i.e. when the maximum force of the cable on the block is not at the maximum value). [3] Fig. 2.4 [Total: 9] 3 (a) (i) By reference to the direction of propagation of energy, state how plane-polarised light differs from unpolarised light. [2] (ii) Explain why sound waves cannot be polarised. [1] (b) Light from a laser incident normally on an ideal polarising filter. The polarising filter is slowly rotated about a horizontal axis that is parallel to the incident light as shown in Fig. 3.1. Fig. 3.1 It was observed that the intensity of the emerging light varies from Io to 0. (i) State what may be deduced from this observation. [1] cable T 30 m

7 NYJC 2023 9749/02/J2Prelim/23 [Turn over (ii) On Fig. 3.2, sketch a graph to show how the intensity of the emerging light may vary with the angle θ which the filter is rotated. [2] Fig. 3.2 (c) Fig. 3.3 shows a beam of sunlight that is reflected from a surface and passes through a vertical polarising filter. Fig. 3.3 The light that reflects from the surface is an unequal mixture of vertically polarised and horizontally polarised light. When the polarising direction of the filter is vertical, the intensity of the emergent light is 0.262 Io. When the polarising direction of the filter is horizontal, the intensity is 0.850 Io. Determine the intensity of the emergent light when the polarising direction of the filter is 30o from the vertical. intensity = Io [2] [Total: 8]

8 NYJC 2023 9749/02/J2Prelim/23 4 (a) Explain what is meant by a field of force. [1] (b) State one similarity and one difference between the fields produced by an isolated point charge and by an isolated point mass. similarity: difference: [2] (c) An isolated solid metal s