2025 RI H2 Physics Prelims P3 Section A Questions

This document has 18 pages. RAFFLES INSTITUTION PRELIMINARY EXAMINATION 2025 Higher 2 CANDIDATE NAME CLASS INDEX NUMBER CLASS 2 5 S 0 PHYSICS Paper 3 Longer Structured Questions Section A 9749/03 24 September 2025 2 hours You must answer on the question paper. No additional materials are needed. INSTRUCTIONS • Use a black or dark blue pen. You may use an 2B pencil for any diagrams or graphs. • Write your name, index number and class in the spaces at the top of the page. • Write your answer to each question in the space provided. • Do not use an erasable pen. Do not use correction fluid or tape. • You may use an approved calculator. Section A Answer all questions. Section B Answer one question only. You are advised to spend one and a half hours on Section A and half an hour on Section B. The number of marks for each question or part question is shown in brackets [ ]. For Examiner’s Use 1 / 7 2 / 7 3 / 10 4 / 10 5 / 8 6 / 10 7 / 8 8 / 20 9 / 20 Deduction Total / 80

2 © Raffles Institution Data speed of light in free space c = 3.00  108 m s−1 permeability of free space 0 = 4  10−7 H m−1 permittivity of free space 0 = 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 s = 21 2ut at+ 2v = 2 2u as+ work done on/by a gas W = pV hydrostatic pressure p = ρgh gravitational potential  = Gm r− temperature T / K = / C 273.15T + pressure of an ideal gas p = 21 3 Nm cV mean translational kinetic energy of an ideal gas molecule E = 3 2 kT displacement of particle in s.h.m. x = 0 sinxt  velocity of particle in s.h.m. v = 0 cosvt  22 0xx=  − electric current I = Anvq resistors in series R = 12 RR++ resistors in parallel 1/R = 121 1 RR++ electric potential V = 4 Q r  alternating current/voltage x = 0 sinxt  magnetic flux density due to a long straight wire B = 0 2 d   I magnetic flux density due to a flat circular coil B = 0 2 N r  I magnetic flux density due to a long solenoid B = 0n I radioactive decay x = ( )0 expxt − decay constant  = 12ln2 t

3 © Raffles Institution [Turn over Section A Answer all the questions in the spaces provided. 1 A ball is released from rest at the 80th floor of a very tall building. The height of each floor of the building is 3.0 m and the point of release is 240 m from the ground level as shown in Fig. 1.1. Fig. 1.1 (a) You can assume that air resistance is negligible. (i) Determine the time taken for the ball to fall from the 60th floor to the 50th floor. time = s [2] (ii) Explain why the time taken to fall from the 50th floor to the 40th floor is shorter than your answer in (i). [1] (iii) Determine the speed of the ball when it reaches the ground. speed = m s−1 [2] 80th floor (240 m) 60th floor (180 m) 50th floor (150 m) 40th floor (120 m) very tall building ground level

4 © Raffles Institution (b) In practice, air resistance is not negligible. The ball is released from rest at the 80 th floor at time t = 0. It reaches terminal velocity at t = tA and hits the ground at t = tB. On the axes of Fig. 1.2, sketch a graph to show the variation with time t of displacement s from the 80th floor of the ball. Numerical values are not required. Fig. 1.2 [2] [Total: 7] s / m t / s 0 0 tB tA

5 © Raffles Institution [Turn over 2 Fig. 2.1 shows two skaters A and B moving along the same straight line towards each other in an amusement park with speeds of 11 m s−1 and 5.0 m s−1 respectively just before they collide. The masses of skaters A and B are 60 kg and 90 kg, respectively. Fig. 2.1 (a) State the principle of conservation of momentum. [1] (b) Assuming that the collision is elastic, s how that skater A moves towards the left with a speed of 8.2 m s−1 after the collision. [2] 5.0 m s−1 11 m s−1 wall A B

6 © Raffles Institution (c) After the collision, skater A hits the wall and bounces off the wall with a speed of 1.0 m s−1. (i) The variation with time t of the force F that the wall exerts on skater A is shown in Fig. 2.2. Fig. 2.2 Determine the maximum force exerted by the wall on skater A. maximum force = N [2] (ii) Explain how the walls in the amusement park can be made safer so that the maximum force exerted on the skater is reduced. [2] [Total: 7] 0 0.10 0.20 0.30 0.40 0.50 t / s F / N

7 © Raffles Institution [Turn over 3 A bow works by storing potential energy in its bent limbs when the bowstring is pulled back, and then converting that potential energy into kinetic energy when the string is released, propelling the arrow forward. Two types of bows, the recurve bow and compound bow are shown in Fig. 3.1. Fig. 3.1 The draw d refers to the distance a bowstring is pulled back. Fig. 3.2 shows the variation with d of the force F required to pull the bowstring of a recurve bow and a compound bow. The maximum draw of both bows is 0.60 m. Fig. 3.2 0 50 100 150 200 250 300 350 0 0.1 0.2 0.3 0.4 0.5 0.6 recurve bow compound bow d / m F / N recurve bow compound bow limb limb limb limb bowstring bowstring

8 © Raffles Institution (a) An arrow of mass 32 g is shot from the recurve bow when bow is at maximum draw of d = 0.60 m. (i) Use Fig. 3.2 to determine the speed of the arrow as it leaves the recurve bow. State any assumption made. speed = m s--1 [3] (ii) Use Fig. 3.2 to explain an advantage of the compound bow over the recurve bow at maximum draw. [1] (b) Explain why the bowstring of any fully drawn bow should not be released without an arrow. [1]

9 © Raffles Institution [Turn over (c) An archer is at a distance of less than 50 m away from a tree as shown in Fig. 3.3. Fig. 3.3 The archer fires an arrow with a speed of 52 m s−1 at an angle of 15 above the horizontal from a height of 1.5 m above the ground. The arrow hits the tree at a height of 8.0 m above the ground. The mass of the arrow is 32 g. The length of the arrow and air resistance are negligible. (i) Determine the kinetic energy of the arrow just before it hits the tree. kinetic energy = J [2] (ii) Calculate the distance of the tree from the archer. distance = m [3] [Total: 10] 8.0 m 1.5 m 15 less than 50 m 52 m s−1

10 © Raffles Institution 4 A distant star S of mass M and its planet P of mass 0.12M orbit in circular orbits about a fixed point O with angular veloc