(SAJC) 2024 H2 Phy Prelim P1 qn and soln for sharing

1 SAJC Prelims 2024 9749/01 [Turn Over Class Index Number Name 23S ST. ANDREW’S JUNIOR COLLEGE JC 2 2024 Preliminary Examination _________________________________________________________________________ PHYSICS, Higher 2 9749/01 Paper 1 Multiple Choice 12th September 2024 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, index number and Civics Group on the Answer Sheet in the spaces provided. There are thirty questions in 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. 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. For Examiner’s Use Total / 30

2 SAJC Prelims 2024 9749/01 [Turn Over This document consists of 20 printed pages including this page. Data speed of light in free space c = 3.00 x 108 m s-1 permeability of free space μo = 4 π x 10-7 H m-1 permittivity of free space εo = 8.85 x 10-12 F m-1 = (1/(36π)) 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 NA = 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 Formulae uniformly accelerated motion s = u t + ½ a t2 v2 = u2 + 2 a s work done on/by a gas W = p ΔV hydrostatic pressure p = ρ g h gravitational potential φ = temperature T / K = T / oC + 273.15 pressure of an ideal gas p = 1 3 𝑁𝑚 𝑉 〈𝑐2〉 mean translational kinetic energy of an ideal gas molecule E = kT displacement of particle in s.h.m. x = xo sin ω t velocity of particle in s.h.m. v = v0 cos ω t v = ± ω electric current I = Anvq resistors in series R = R1 + R2 + ... resistors in parallel 1 / R = 1 / R1 + 1 / R2 + ... electric potential V = alternating current/voltage x = xo sin ω t magnetic flux density due to a long straight wire B = 𝜇0𝐼 2𝜋𝑑 magnetic flux density due to a flat circular coil B = 𝜇0𝑁𝐼 2𝑟 magnetic flux density due to a long solenoid B = 𝜇0𝑛𝐼 radioactive decay x = xo exp (-λ t)

3 SAJC Prelims 2024 9749/01 [Turn Over decay constant λ =

4 SAJC Prelims 2024 9749/01 [Turn Over Answer all questions. 1 A student determines the acceleration of free fall by using a small metal ball, as shown. When switch S is opened, the ball is released from an electromagnet and an electronic timer is started. The ball then falls vertically downwards. The timer stops when the ball hits a trapdoor. The student measures the distance PQ between the electromagnet and the trapdoor. This distance and the reading on the timer are then used to calculate the acceleration of free fall. Which statement about errors in the experiment is correct? A The random error can be reduced by subtracting the diameter of the ball from the distance PQ. B The random error can be reduced by adding the diameter of the ball to the distance PQ. C The systematic error can be reduced by subtracting the diameter of the ball from the distance PQ. D The systematic error can be reduced by adding the diameter of the ball to the distance PQ.

5 SAJC Prelims 2024 9749/01 [Turn Over 2 A student takes measurements to determine the constant acceleration of a model car moving from rest in a straight line. The measured values with their absolute uncertainties are as shown. The student uses the equation s = 1/2 at2 to calculate the acceleration of the car. What is the acceleration and its absolute uncertainty? A (0.11 ± 0.01) m s–2 B (0.11 ± 0.02) m s–2 C (0.15 ± 0.01) m s–2 D (0.15 ± 0.02) m s–2

6 SAJC Prelims 2024 9749/01 [Turn Over 3 A parachutist falls from a stationary balloon at time t = 0. The velocity –time graph for the parachutist from time t = 0 until the time when he is just above the ground is shown. Which graph best shows the variation with time of the acceleration of the parachutist?

7 SAJC Prelims 2024 9749/01 [Turn Over 4 A clay pigeon is launched vertically into the air from the ground. A marksman lies 170 m away from the launching device on level ground. Just as the clay pigeon reaches its maximum height of 60 m, the marksman fires a bullet aimed directly at the clay pigeon. The bullet leaves the rifle with a speed of 300 m s –1. Assume air resistance is negligible. At what time after the bullet is fired is the clay pigeon hit? A 0.17 s B 0.57 s C 0.60 s D 1.66 s

8 SAJC Prelims 2024 9749/01 [Turn Over 5 An object of mass m, moving at speed u along a frictionless horizontal surface, collides head-on with a stationary object of mass 4m. After the collision, the object of mass m rebounds along its initial path with 1 4 of its kinetic energy before the collision. What is the speed of the object of mass 4m after the collision? A 𝑢 8 B 3 𝑢 16 C 5 𝑢 16 D 3 𝑢 8 6 A uniform sphere of weight 15 N is placed in between two smooth planes as shown. What is the magnitude of the force exerted by the vertical plane on the sphere? A 0 N B 7.5 N C 8.7 N D 26 N 60 vertical plane slanted plane sphere

9 SAJC Prelims 2024 9749/01 [Turn Over 7 A lamp is suspended in equilibrium from a fixed support by three long identical wires. The weight of the lamp causes each wire to have an extension of 0.40 cm. The height h of the lamp above the floor is measured. The middle wire suddenly breaks and the lamp falls a small distance as the extensions of the remaining two wires increase. The wires obey Hooke’s law. When the lamp is in equilibrium, the height h of the lamp above the floor is measured again. What is the difference between the two values of h? A 0.20 cm B 0.27 cm C 0.40 cm D 0.60 cm 8 A uniform bar of length L and weight W rests horizontally on two supports X and Y. Support X exerts a vertical force RX from one end of the bar while support Y exerts a vertical force RY at the other end of the bar as shown. The bar is in equilibrium. What is the ratio 𝑅𝑥 𝑅𝑦 ? A 3 2 B 2 3 C 3 5 D 2 5

10 SAJC Prelims 2024 9749/01 [Turn Over 9 A car is driven from rest along a straight horizontal road. The car engine exerts a constant driving force. Friction and air resistance are negligible. How does the power developed by the engine change with the distance travelled? A Power does not change B Power decreases linearly C Power increases linearly D Power increases non-linearly 10 Two satellites, A and B, each of mass 14.6 kg, are launched into circular orbits about the Earth’s center. Satellite A is to orbit at an altitude of 6370 km while satellite B is to orbit at an altitude of 14100 km. Which satellite has the greater total energy? A Satellite A B Satellite B C Both satellites have the same total energy. D There is not enough information to determine the total energy.