2025 NYJC H2 Phy 9749 P1 Answers

NYJC 2025 9749/01/J2Prelim/25 [Turn over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME Solution CLASS TUTOR’S NAME CENTRE NUMBER S INDEX NUMBER PHYSICS 9749/01 Paper 1 Multiple Choice 24 September 2025 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class, Centre number and index number in the spaces at the top of this page. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 15 printed pages. H

2 NYJC 2025 9749/01/J2Prelim/25 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 2025 9749/01/J2Prelim/25 [Turn over 1 A single sheet of aluminium foil is folded twice to produce a stack of four sheets. The total thickness of the stack of sheets is measured to be (0.80  0.02) mm. This measurement is made using a digital calliper with zero error of (−0.20  0.02) mm. What is the percentage uncertainty in the calculated thickness of a single sheet? A 1.0% B 2.0% C 4.0% D 6.7% Ans: C ( ) ( ) 4 1.00 0.04 mm 0.25 0.01 mm t t = = 0.01100% 100%0.25 4.0% t t   =  = 2 A voltmeter connected across a resistor in a circuit gives readings which have high precision but low accuracy. Which of the following best describes the likely error in readings taken with this voltmeter? random error systematic error A high high B high low C low high D low low Ans: C

4 NYJC 2025 9749/01/J2Prelim/25 3 A stone falls vertically and strikes soft ground with speed u. The stone experiences constant deceleration until it comes to rest. Which graph shows the variation of speed v with distance s below the ground surface? A B C D 22 2 2 Ans: A Take downward as positive. Below ground surface, acceleration is upward, which is thus negative. Let this acceleration be - . 2 2 2 Using GC, the graph will give be similar to op v u as v u as v u s   =+ =+ =− tion A. 4 A particle X with kinetic energy Ek collides with a stationary particle Y. Both particles have the same mass. After colliding, X and Y travel together as a single particle. How much kinetic energy is lost in the collision? A zero B 4 kE C 2 kE D 3 4 kE s s s s v u v u v u v u Ans: C 2 2 2 2 2 1 2 2 1 1 1 1 22 2 2 2 4 4 2 k ff if 2 k E = mv By principle of conservation of momentum, vmv + 0 = 2mv v loss inKE KE KE Evvmv m mv m mv →= =− = − = − = =   ()

5 NYJC 2025 9749/01/J2Prelim/25 [Turn over 5 A sphere of mass 3.0 kg travelling due North at 2.0 m s−1 collides with another sphere of mass 4.0 kg travelling due East at 2.0 m s−1. The magnitude of their resultant momentum after the collision will be A 2.0 kg ms–1. B 10 kg m s–1. C 14 kg m s–1. D dependent on whether the the collision is elastic or inelastic. Ans: B Using vector addition, resultant initial momentum = 10 kg m s-1 Since the final momentum = initial momentum (PCOM), Magnitude of resultant momentum after collision is 10 kg m s-1

6 NYJC 2025 9749/01/J2Prelim/25 6 A block and a sphere of equal mass m are placed on an inclined plane. If the maximum frictional force that can exist between the block and the plane is equal to the weight of the block, and there is no frictional force between the sphere and the plane, what is the maximum angle θ at which the plane can be inclined before the block starts to slip? A 30° B 45° C 60° D 73° Ans: A Considering the net force on the block along the inclined plane, Wblock + Fby sphere on block – Ffriction by plane on block = 0 mg sin θ + mg sin θ – f = 0 Since the frictional force is f, when the block just starts to slip, f = mg. 2mg sin θ – mg = 0 sin θ = 0.5 θ = 30° 7 Blocks A and B, of masses 4.0 kg and 6.0 kg respectively, are connected by a light cord passing over a light, frictionless pulley. Block A is held at rest on a rough slope inclined at 30° to the horizontal as shown. When A and B are released, block A experiences a constant frictional force of 3.0 N. What is the total kinetic energy of A and B when B has travelled 2.0 m downwards? A 39 J B 72 J C 78 J D 118 J θ B 30 2.0 m Ans: B Loss in GPE of B = Gain in GPE of A + Gain in KE of A and B + Work done agst friction 6.0(9.81)(2.0) 4.0(9.81)(2.0sin30) 3.0(2.0 ) 72 J AB AB KE KE + + = + + =

7 NYJC 2025 9749/01/J2Prelim/25 [Turn over 8 A wire is stretched elastically by a force of 200 N, causing an extension of 2.00 mm. The force is gradually increased to 250 N, and the wire remains within its elastic limit. What is the work done in stretching the wire from 200 N to 250 N? A 0.113 J B 0.225 J C 113 J D 225 J Ans: A 1200 100 000 N m0.002 Area under graph for additional extension 1 250work done (200 250)( 0.002)2 100000 0.113 J F kx k − = == = + − = F 0 2.0 250 x / mm 200

8 NYJC 2025 9749/01/J2Prelim/25 9 A small mass is attached to a light string and rotates in a vertical circle of radius r. Taking g to be acceleration of free fall, what is the centripetal acceleration of the mass when it is at the lowest point of motion if the speed of the mass at the highest point just allow the mass to complete the circular motion? A g B 2g C 4g D 5g Ans: D 2 2 22 2 2 2 At the top of circle, 0 By conservation of energy, 11 (2 )22 11( ) (2 )22 5 5 top top top bottom bottom bottom bottom c mvT mg mg r v rg mv mg r mv rg g r v v rg vag r + = + = = += += = == r mass

9 NYJC 2025 9749/01/J2Prelim/25 [Turn over 10 Two satellites P and Q orbit the Earth due to the gravitational field of the Earth. P and Q are at dist