2025 HCI C2 Prelim H2 Physics P3 QP

This paper (comprising booklets 1 and 2) consists of 30 printed pages, including 1 blank page. HWA CHONG INSTITUTION JC2 Preliminary Examination Higher 2 CANDIDATE NAME CT GROUP 24S CENTRE NUMBER INDEX NUMBER PHYSICS Paper 3 Longer Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 9749/03 19 September 2025 2 hours INSTRUCTIONS TO CANDIDATES Write your Centre number, index number, name and CT class clearly on all 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 or rough working. Do not use staples, paperclips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Section A Answer all questions. Section B Answer one question only. Circle the question number on the cover page. You are advised to spend one and a half hours on Section A and half an hour on Section B. The number of marks is given in brackets [ ] at the end of each question or part question. You are reminded of the need for good English and clear presentation in your answers. For Examiner’s Use Section A 1 8 2 6 3 8 4 8 5 10 6 10 7 10 Section B (choose ONE) 8 20 9 20 Deductions Total 80 Booklet 1

2 © Hwa Chong Institution 9749 / 03 / Preliminary Examination 2025 Data Formulae speed of light in free space, c = 3.00  10 8 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  10 23 mol -1 the Boltzmann constant, k = 1.38  10 -23 J K -1 gravitational constant, G = 6.67  10 -11 N m 2 kg -2 acceleration of free fall, g = 9.81 m s -2 uniformly accelerated motion work done on / by a gas hydrostatic pressure gravitational potential temperature pressure of an ideal gas mean kinetic energy of a molecule of an ideal gas displacement of particle in s.h.m. velocity of particle in s.h.m. electric current resistors in series resistors in parallel electric potential alternating current / voltage magnetic flux density due to a long straight wire magnetic flux density due to a flat circular coil magnetic flux density due to a long solenoid radioactive decay decay constant s = ut + 2 1 at2 v 2 = u 2 + 2as W = p V p = gh r Gm−= T/K = T/ C + 273.15 P = 21 3 Nm cV  3 2 E kT= x = xo sin t v = vo cos t = )( 22 xxo −  I = Anvq R = R1 + R2 + . . . 1/R = 1/R1 + 1/R2 + . . . r QV o4= x = xo sin  t 2 oμB d=  I 2 oμNB r= I B = onI x = xo exp (−t ) 1 2 ln2 t =

3 © Hwa Chong Institution 9749 / 03 / Preliminary Examination 2025 Section A Answer all questions in the spaces provided. 1 A ball is thrown from point S, as shown in Fig. 1.1. The initial velocity of the ball is 25 m s-1 at an angle to the horizontal of 30.0°. The ball lands at point F. The points S and F are at the same horizontal level. (a) (i) Calculate the vertical component of the ball’s initial velocity. vertical component = ………………………. m s-1 [1] (ii) Show that the maximum height reached by the ball is 8.0 m, assuming air resistance is negligible. [1] Fig. 1.1 30.0 25 m s-1 S F

4 © Hwa Chong Institution 9749 / 03 / Preliminary Examination 2025 [Total: 8 marks] (iii) The kinetic energy of the ball at S is K. Calculate the kinetic energy and the potential energy of the ball in terms of K at a height of 8.0 m, kinetic energy = ………………………… potential energy = …..……………………. [3] (b) The horizontal distance from S to F is x. On Fig. 1.2, sketch the variation with the horizontal distance of (i) the potential energy of the ball and label the graph as Ep. (ii) the kinetic energy of the ball and label the graph as Ek. [3] 0 horizontal distance energy Fig. 1.2

5 © Hwa Chong Institution 9749 / 03 / Preliminary Examination 2025 2 (a) The drag force Fd on a car moving through air is given by the formula: 21 2 ddF C Av= where  is the air density, Cd is the unitless drag coefficient, A is the frontal area of the car, and v is the velocity of the car. Table 2.1 shows the data measured for car A. Table 2.1  / kg m-3 Cd A / m2 v / km h-1 1.20  0.05 0.30  0.02 2.50  0.05 108  2 Use this data to calculate the drag force Fd on car A and its associated uncertainty. Fd   Fd = …………………………… N [3]

6 © Hwa Chong Institution 9749 / 03 / Preliminary Examination 2025 [Total: 6 marks] (b) Cars A and B approach a junction as shown in Fig. 2.2. Car A travels east at a constant speed of 40.0 km h-1 while car B travels northwest at a constant speed of 50.0 km h-1. With the aid of a vector diagram, determine the velocity of car A relative to car B. velocity of car A relative to car B = …………………………… km h-1 direction: ………………........……………………………………………………………………………. [3] car B car A Fig. 2.2 N

7 © Hwa Chong Institution 9749 / 03 / Preliminary Examination 2025 3 Planet Z is spherical and has a uniform density. It has only argon in its atmosphere. (a) The escape velocity is the minimum velocity required to escape the gravitational pull of a celestial body. Show that the escape velocity v of Planet Z is given by 28 3v G r = where r is the radius, and  is the density of Planet Z. [2] (b) Given that Planet Z has a mean density of 5500 kg m -3 and radius of 413 km, calculate the escape velocity of the argon gas molecules at its surface. v = …………………………. m s-1 [1]

8 © Hwa Chong Institution 9749 / 03 / Preliminary Examination 2025 [Total: 8 marks] (c) Argon gas behaves as an ideal monatomic gas on Planet Z, and it has a molar mass of 40 g mol-1. Assume that the root-mean-square speed of the argon molecules is equal to the escape velocity. Using Kinetic Theory, determine the absolute temperature of the atmosphere on Planet Z. absolute temperature = ………………… K [3] (d) Suppose the atmosphere of Planet Z is 100 K lower than the temperature calculated in (c). Suggest a reason whether argon gas molecules would be able to escape from the atmosphere of Planet Z. ……………………………………………………………………………………………………..…