AJC H2 PHY P2

1 9749/02/AJC2017/Prelim [Turn Over Name: _____________________________ ( ) PDG: ______/ 16 2017 JC2 Preliminary Examination PHYSICS Higher 2 9749/02 Paper 2 Structured Questions Tuesday 12 September 2017 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class index number and PDG in the spaces provided above. 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, glue or correction fluid. The use 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. ANDERSON JUNIOR COLLEGE This document consists of 22 printed pages For Examiner’s Use 1 2 3 4 5 6 7 Significant Figure Total (80 marks)

2 9749/02/AJC2017/Prelim Data speed of light in free space c  3.00 x 108 m s-1 permeability of free space 0  4 x 10-7 H m-1 permittivity of free space 0  8.85 x 10-12 F m-1 (1/(36 )) x 10-9 F m-1 elementary charge e  1.60 x 10-19 C the Planck constant h  6.63 x 10-34 J s unified atomic mass constant u  1.66 x 10-27 kg rest mass of electron me 9.11 x 10-31 kg rest mass of proton mp  1.67 x 10-27 kg molar gas constant R  8.31 J K-1 mol-1 the Avogadro constant N A  6.02 x 1023 mol-1 the Boltzmann constant k  1.38 x 10-23 J K-1 gravitational constant G  6.67 x 10-11 N m2 kg-2 acceleration of free fall g  9.81 m s-2

3 9749/02/AJC2017/Prelim [Turn Over Formulae uniformly accelerated motion s 2 2 1 atut  2v asu 22  work done on/by a gas W Vp hydrostatic pressure p gh gravitational potential  r Gm temperature T/K  T/C + 273.15 pressure of an ideal gas p   2 3 1 cV Nm mean translational kinetic energy of an ideal gas molecule E kT2 3 displacement of particle in s.h.m. x  x0 sin  t velocity of particle in s.h.m. v  v0 cos  t  22 xxo  electric current I  Anvq resistors in series R  R1 + R2 + … resistors in parallel 1/R  1/R1 + 1/R2 + … electric potential V  r Q o4 alternating current/voltage x  x0 sin  t magnetic flux density due to long straight wire B  d o   2 I magnetic flux density due to a flat circular coil B  r No 2 I magnetic flux density due to a long solenoid B  Ino radioactive decay x  x0 exp(–t) decay constant   2 1 2ln t

4 9749/02/AJC2017/Prelim 1 In 2010, an iron cannon and some iron cannon balls were discovered offshore in the United Kingdom after sitting on the seabed for a few hundred years. (a) An experiment is performed to determine the density ρ of an iron cannon ball. The average of the measurements, with their uncertainties, are shown in Fig 1.1. Mass, m / kg Diameter, d / cm 79.72 ± 0.01 26.7 ± 0.1 Fig 1.1 (i) Show that the density of iron, ρ is 7999 kg m-3. [1] (ii) Calculate the actual uncertainty in ρ. actual uncertainty in ρ =…………………….. kg m -3 [2] (iii) State the value of ρ and its actual uncertainty to the appropriate number of significant figures. ρ = ……………………±………….………..kg m -3 [1]

5 9749/02/AJC2017/Prelim [Turn Over (b) One possible way to raise the iron cannon from the seabed is to use a lifting bag, which may be attached to the iron cannon and then partially inflated with air, as shown in Fig. 1.2. Fig. 1.2 (i) The submerged iron cannon of mass 800 kg is attached to a lifting bag of negligible volume and mass. Using the data in part (a)(i), estimate the initial acceleration of the cannon when 0.70 m 3 of air is suddenly released into the bag. The density of the seawater is 1050 kg m-3. acceleration = ……………………………m s -2 [3] (ii) Explain why air has to be released continuously from the lifting bag as the iron cannon rises from the seabed to the surface so that a constant speed of ascent is maintained. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [3] lifting bag iron cannon seabed

6 9749/02/AJC2017/Prelim 2 (a) Gas, R, is trapped in a vessel by a column of liquid PQ as shown in Fig 2.1 below. Length of the liquid column can be increased by adding more liquid to PQ. Fig 2.1 Using the kinetic theory, explain how the pressure of the gas R is increased, (i) when the volume of R remain unchanged and its temperature increases. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. …………………………………………………………………………………………….[3] (ii) when the temperature of R remain unchanged and its volume decreased slightly. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. …………………………………………………………………………………………….[2] (b) There is about one hydrogen atom per cm 3 in outer space, where the temperature (in the shade) is about 3.5 K. The mass of a hydrogen atom is 1 u. Calculate (i) the rms speed of these atoms. rms speed = …………………………….. m s -1 [3] Q P R

7 9749/02/AJC2017/Prelim [Turn Over (ii) the pressure exerted by these atoms. pressure = ………………………………… Pa [3] 3 (a) A mass of 170 g oscillates with simple harmonic motion. Fig. 3.1 shows the variation with time t of the displacement y of the mass. (i) Explain what is meant by simple harmonic motion. ………….……………………………………………………………………….………..…….. ………….……………………………………………………………………….………..…….. …………....…………………………………………………………………………………. [2] Fig. 3.1

8 9749/02/AJC2017/Prelim (ii) On Fig. 3.2, draw a graph showing the variation with displacement y of the potential energy Ep of the mass . [3] (b) The drums of an automatic washing machine are suspended from the casing by springs, at the top and bottom, as shown in Fig. 3.3. The inner drum rotates within the outer drum at variable speeds according to the washing programme. Fig. 3.3 The total mass of the drums is 20 kg. A block of concrete of mass 20 kg is added to the outer drum. The natural period of oscillation of the system is 1.6 s. The period of oscillation T of the system is given by k MT 2 , where M is the total mass of the load in the system and k is the effective spring constant of the springs. Ep / mJ y / cm 1.0 2.0 3.0 -3.0 -2.0 -1.0 0 Fig. 3.2 inner dr