2018 MJC P1 Soln

This document consists of 18 printed pages. [Turn over MERIDIAN JUNIOR COLLEGE JC2 Preliminary Examinations Higher 2 H2 Physics 9749/01 Paper 1 Multiple Choice 20 September 2018 1 hour Additional Materials: Optical Mark Sheet (OMS) Class Reg No Candidate Name: READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and index number on the Answer Sheet in the spaces provided. There are thirty questions in this section. 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 Answer Sheet. In the Index Number section, shade your index number using the first two spaces (e.g. index number 5 should be entered as “05”). Ignore the remaining numbers and letters. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate.

Meridian Junior College H2 Physics Paper 1 JC2 Preliminary Examinations 2018 2 20 September 2018 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 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

Meridian Junior College H2 Physics Paper 1 JC2 Preliminary Examinations 2018 3 20 September 2018 [Turn over Formulae uniformly accelerated motion s = 21 2ut at v2 = u2 + 2as work done on/by a gas W = p V hydrostatic pressure p = gh gravitational potential = /G m r temperature T /K = T /°C + 273.15 pressure of an ideal gas p = 21 3 Nm cV mean translation kinetic energy an ideal gas molecule E = 3 2 kT displacement of particle in s.h.m. x = xo sin t velocity of particle in s.h.m. v = vo cos t v = 2 2 ox x electric current I = Anvq resistors in series R = 1 2R R … resistors in parallel 1/ R = 1 21/ 1/R R … electric potential V = 04 Q r alternating current/voltage X = xo sin t 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 expx t decay constant = 1 2 ln2 t

Meridian Junior College H2 Physics Paper 1 JC2 Preliminary Examinations 2018 4 20 September 2018 1 B 11 D 21 D 2 C 12 C 22 A 3 D 13 A 23 A 4 C 14 C 24 A 5 D 15 B 25 A 6 A 16 A 26 C 7 C 17 B 27 B 8 B 18 B 28 B 9 B 19 D 29 D 10 C 20 B 30 A 1 A student measures the time t for a ball to fall from rest through a vertical distance h. The student plots his results and best-fit line in the graph shown. Which of the following statement is true? A The result is accurate as the line is close to the data points B The result is not accurate as the line does not pass through the origin C Data is precise as there are equal number of data points on both sides of the line D Data is precise as the data points do not deviate from the line Ans: (B) At time = 0, the height fallen should be zero since the ball is still at the starting point. 2 The experimental measurement of the heat capacity of a solid as a function of temperature T is found to fit the following expression 3C T T What are the possible base units of and ? units of units of 0 t

Meridian Junior College H2 Physics Paper 1 JC2 Preliminary Examinations 2018 5 20 September 2018 [Turn over A kg m2 s 1 K 4 kg m2 s 1 K 1 B kg2 m s 2 K 3 kg2 m s 2 K 2 C kg m2 s 2 K 4 kg m2 s 2 K 2 D kg2 m s 2 K 3 kg2 m s 2 K 1 Ans: (C) 3 1 3 2 2 2 2 2 1 3 J K K K 1Using J kg m s2 kg m s K K K C T T E mv 3 A motorcycle stunt -rider moving horizontally takes off from a point 1.25 m above the ground, landing 10 m away as shown in the diagram. What was the speed at take-off? A 5 m s–1 B 10 m s–1 C 15 m s–1 D 20 m s–1 Ans: D sy = uy t + ½ ay t2 1.25 = 0 + ½ (9.81) t2 t = 0.50 s sx = ux t 10 = ux (0.50) ux = 20 m s–1 4 A body of mass 3.0 kg is thrown with a velocity of 20 m s–1 at an angle of 60 above horizontal. It reaches the maximum height after 1.8 s. Air resistance is negligible. What is the rate of change of momentum of the body at the maximum height? A zero B 17 kg m s–2 C 29 kg m s–2 D 33 kg m s–2 Ans: C rate of change of momentum = net force = weight = 3.0 9.81 = 29 N OR use (mvy – muy)/t = (0 – 3.0 20 sin 60 ) / 1.8 = –29 kg m s–2 5 A body P of mass 2.0 kg and moving with velocity +3.0 m s–1 makes a head-on inelastic collision with a stationary body Q of mass 4.0 kg. Which of the following could be the velocities of P and Q after the collision? 10 m 1.25 m

Meridian Junior College H2 Physics Paper 1 JC2 Preliminary Examinations 2018 6 20 September 2018 velocity of P after collision velocity of Q after collision A +0.5 m s–1 +0.5 m s–1 B +0.0 m s–1 +3.0 m s–1 C –1.0 m s–1 +2.0 m s–1 D –0.6 m s–1 +1.8 m s–1 Ans: D Initial momentum = 2.0 × 3.0 = +6.0 Ns Final momentum = 2.0( 0.6) + 4.0(1.8) = 1.2 + 7.2 = +6.0 Ns only D has momentum conserved but KE not conserved (or has lesser relative speed of separation than relative speed of approach) Both momentum and KE are conserved for C (elastic collision) 6 The diagram shows a body attached to an elastic cord being thrown vertically upwards. Initially the cord is unstretched but after a while it becomes stretched. The cord obeys Hooke’s law and air resistance is ignored. Which of the following shows the variation with displacement of the kinetic energy K, gravitational potential energy G and elastic potential energy E? cord is fixed to a point on the ground directly below the body thrown upwards

Meridian Junior College H2 Physics Paper 1 JC2 Preliminary Examinations 2018 7 20 September 2018 [Turn over Ans: A GPE increases linearly with displacement EPE starts later, increases with extension squared (parabolic upwards) KE decreases linearly with displacement at first (vs GPE), then decreases at greater and greater rate due to increasing EPE 7 A passenger is sitting in a railway carriage facing in the direction in which the train is travelling. A pendulum hangs down in front of him from the carriage roof. The train travels along a circular arc bending to the left. Which one of the following diagrams shows the position of the pendulum as seen by the passenger, and the directions of the forces acting on it? Ans: C 8 In two widely -separated planetary systems whose suns have masses S1 and S2, planet P1 of mass M1 (orbiting sun S1) and planet P2 of mass M2 (orbiting sun S2) are observed to have circular orbits of equal radii. If P1 completes an orbit in half the time taken by P2, it may be deduced that displacement displacement displacement displacement energy energy energy energy K K K K G G G G E E E E A B C D A B C D

Meridian Junior College H2 Physics Paper 1 JC2 Preliminary Examinations 2018 8 20 September 2018 A S1 = S2 and M1 = 0.25 M2 B S1 = 4S2 only C S1 = 4S2 and M1 = M2 D S1 = 0.25 S2 only Ans: (B) 9 A particle of mass 4.0 kg moves in simple harmonic motion. Its potential energy U varies with position x as shown in the figure below. What is the period of