(DHS) 2024 Prelim Phy P2 final

© DHS 2024 9749/02 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 PHYSICS Paper 2 Structured Questions Candidates answer on the Question Paper 9749/02 12 September 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and class at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions 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. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 8 2 11 3 5 4 10 5 7 6 9 7 10 8 20 Total 80 This document consists of 22 printed pages and 2 blank pages.

2 © DHS 2024 9749/02 Data speed of light in free space, c = 3.00 × 108 m s−1 permeability of free space, o = 4 × 10−7 H m−1 permittivity of free space, o = 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

3 © DHS 2024 9749/02 [Turn over Formulae uniformly accelerated motion, s = ut + at2 v2 = u2 + 2as work done on/by a gas, W = pV hydrostatic pressure, p = gh gravitational potential,  = −Gm/r temperature, T/K = T/oC + 273.15 pressure of an ideal gas, p = mean translational kinetic energy of an ideal gas molecule, E = displacement of particle in s.h.m., x = x0 sin t velocity of particle in s.h.m., v = v0 cos t =  electric current, I = Anvq resistors in series, R = R1 + R2 + . . . resistors in parallel, 1/R = 1/R1 + 1/R2 + . . . electric potential, V = alternating current / voltage, x = x0 sin t magnetic flux density due to a long straight wire, B = magnetic flux density due to a flat circular coil, B = magnetic flux density due to a long solenoid, B = radioactive decay, x = x0 exp(−t) decay constant,  = 1 2 21 3 Nm cV  kT2 3 22 xxo − r Q o4 0 2 d I  0 2 N r I 0nI 1 2 ln2 t

4 © DHS 2024 9749/02 Answer all questions in the spaces provided. 1 Fig. 1.1 shows a bomber flying horizontally at a speed of 72 m s −1 and at a height of 100 m above the ground. When directly flying over the origin O, bomb B is released and it strikes a truck T, which is moving along a level road with a constant speed v. At the instant the bomb is released, the truck T is at a distance xo = 125 m from origin O. (a) The trajectory of bomb B after it is released from the bomber is said to be parabolic. Explain qualitatively why the path taken is parabolic. ...…………………………………………………………………………………………….…...... …...……………………………………………………………………………………………..… ……………………………………………………………………………………………….…. [2] (b) Calculate the time of flight of bomb B upon striking the truck T. time of flight = ………….…… s [2] Fig. 1.1 72 m s−1 100 m bomb B truck T x0 x v

5 © DHS 2024 9749/02 [Turn over (c) (i) On Fig. 1.2, sketch graphs showing the variation with time t of the horizontal displacement x, for the bomb B and the truck T. Label the graphs B and T respectively, indicating appropriate values on the graphs. [2] (ii) Use your graphs in (c)(i) or otherwise, determine the speed v of the truck T. v = ………….……………… m s−1 [2] [Total: 8] x / m Fig. 1.2 t / s

6 © DHS 2024 9749/02 2 (a) Fig. 2.1 shows the head-on collision of two blocks on a frictionless surface. Fig. 2.1 Before the collision, the 2.4 kg block is moving to the right with a speed of 3.0 m s−1 and the 1.2 kg block is moving to the left at a speed of 2.0 m s −1. During the collision, the blocks stick together. Immediately after the collision the blocks have a common speed v. (i) State the principle of conservation of momentum. ……………………………………………………………………………………….…....... ……………………………………………………………………………………….…..... [1] (ii) Calculate the speed v. v = …………………………….. m s−1 [2] (iii) Use your answer in (a)(ii) to show that the collision is inelastic. [2]

7 © DHS 2024 9749/02 [Turn over (b) Fig. 2.2 shows a helicopter viewed from above. Fig. 2.2 The blades of the helicopter rotate in a circle of radius 5.0 m. When the helicopter is hovering, the blades propel air vertically downwards with a constant speed of 12 m s−1. Assume that the descending air occupies a uniform cylinder of radius 5.0 m. The density of air is 1.3 kg m−3. (i) Explain, in terms of Newton’s laws of motion, the forces on the helicopter as it is hovering. …...…………………………………….……………………………………………………. ...…………………………………………………………………………………………….. …...…………………………………….……………………………………………………. ...…………………………………………………………………………………………….. …...…………………………………….……………………………………………………. …….………………………………………………………………………………………. [3] (ii) Show that the mass of air propelled downwards is 6100 kg in a time of 5.0 seconds. [1] 5.0 m

8 © DHS 2024 9749/02 (iii) Hence or otherwise, determine the force provided by the rotating helicopter blades to propel this air downwards, force = …………………………….. N [2] [Total: 11] 3 A cylindrical tube, containing some sand, floats upright in a liquid of density , as shown in Fig. 3.1. The tube has a uniform cross-sectional area A. The total mass of the tube and sand is M. The tube is displaced vertically downwards and then released. The tube oscillates vertically. For a displacement x, the acceleration a of the tube is given by the expression a = − ( Ag M )x where g is the acceleration of free fall. Fig. 3.1 area of cross- section A tube sand liquid density 

9 © DHS 2024 9749/02 [Turn over (a) Explain why the expression leads to the conclusion that the tube is performing simple harmonic motion. ...…………………………………………………………………………………………….…...... …...……………………………………………………………………………………………..… ...…………………………………………………………………………………………….…...... …...……………………………………………………………………………………………..… ……………………………………………………………………………………………….…. [3] (b) The mass M of the tube and sand is 130 g. The area of cross -section A of the tube is 5.3 cm 2. Calculate the frequency of oscillation of the tube when floating in a liquid of density  of 1.2 x 103 kg m−3. frequency =...………………….…….. Hz [2] [Total: 5]

10 © DHS 2024 9749/02 4 (a) A circuit consists of four resistors, R1, R2, R3 and R4 of the same resistance R and two ammeters, A1 and A2, as shown in Fig. 4.1. The resistance measured between terminals X and Y is 2.4 Ω. Show that the value of resistance R is 6.0 Ω. [1] (b) A cell of e.m.f. 1.5 V and internal res