SAJC 2022 Prelim P1 QP + Guide

1 SAJC Prelims 2022 9749/01 [Turn Over Class Index Number Name 21S ST. ANDREW’S JUNIOR COLLEGE JC 2 2022 Preliminary Examination _________________________________________________________________________ PHYSICS, Higher 2 9749/01 Paper 1 Multiple Choice 16th September 2022 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 This document consists of 14 printed pages including this page.

2 SAJC Prelims 2022 9749/01 [Turn Over Data speed of light in free space c = 3.00 x 108 m s-1 permeability of free space o = 4  x 10-7 H m-1 permittivity of free space o = 8.85 x 10-12 F m-1 = (1/(36)) 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 V hydrostatic pressure p =  g h gravitational potential  = r Gm− 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 = 2 3 kT displacement of particle in s.h.m. x = xo sin  t velocity of particle in s.h.m. v = v0 cos  t v =   22 0 xx − electric current I = Anvq resistors in series R = R1 + R2 + ... resistors in parallel 1 / R = 1 / R1 + 1 / R2 + ... electric potential V = r Q 04 alternating current/voltage x = xo sin  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 (- t) decay constant  = 2/1 2ln t

3 SAJC Prelims 2022 9749/01 [Turn Over Answer all questions. 1 The table below shows estimates of some physical quantities. Which quantity is not a reasonable estimate? quantity estimate A electric current in a heater 12 A B mass of an adult person 70 kg C maximum speed of an Olympic sprinter 10 m s–1 D water pressure at the bottom of a swimming pool 107 Pa 2 The energy E stored in a certain electronic component is given by 2= nQE k where Q is the total charge in the component, n is an unknown integer and k is a physical quantity with SI base units A2 s4 kg-1 m-2. What is the value of n? A -2 B -1 C 1 D 2 3 A micrometer is used to measure the diameters of two cylinders. diameter of first cylinder = (12.78  0.02) mm diameter of second cylinder = (16.24  0.03) mm The difference in the diameters is calculated. What is the percentage uncertainty in this difference? A 0.29 B 0.58 C 0.87 D 1.4

4 SAJC Prelims 2022 9749/01 [Turn Over 4 A driver decelerates uniformly to a stop as he approaches a junction, turns around immediately, and accelerates at the same rate that he decelerated earlier. Which of the following velocity-time and acceleration-time graphs best represents this motion? A B C D v / m s-1 t / s a / m s -2 t / s v / m s-1 t / s a / m s -2 t / s v / m s-1 t / s a / m s -2 t / s v / m s-1 t / s a / m s -2 t / s

5 SAJC Prelims 2022 9749/01 [Turn Over 5 Mass M has the same kinetic energy as mass m. What is the ratio of their momenta m M p p ? A M mM + B mM M + C m M D M m 6 A resultant force of 5 N acts on a body for a time of 4.0 s. Which graph could show the variation with time t of the momentum p of the body? 7 A cup contains 100 g of water. The pressure at the bottom of the cup is P. before after 50 g of water is removed from the cup, frozen into ice, and added back to the cup, as shown above. 10% of the volume of the ice is above the surface of the water. What is the new pressure at the bottom of the cup? A 0.95P B P C 1.05P D 1.10P A B C D

6 SAJC Prelims 2022 9749/01 [Turn Over 8 The variation of the extension x of a light spring with the force F applied is shown below. Slotted masses with a total weight of 3.0 N were initially hung on the spring. What is the decrease in the elastic potential energy stored in the spring when a slotted mass weighing 0.5 N is removed from the system? A 0.013 J B 0.015 J C 0.028 J D 0.056 J 9 A lorry of mass 2000 kg has an engine which can deliver a maximum power of 50 kW. What is the minimum time in which the lorry can be accelerated from rest to a speed of 100 km h-1 on level ground? A 11.3 s B 15.4 s C 30.9 s D 200 s x / cm F / N 10 5.0 0

7 SAJC Prelims 2022 9749/01 [Turn Over 10 Two blocks of mass 10.0 g and 21.0 g are tied together and performing a uniform horizontal circular motion on a smooth table, at an angular speed of 6.28 rad s-1, as shown below. Tension T1 is the tension in the string connecting the 21.0 g mass to the centre and T2, the tension in the string connecting the 10.0 g mass to the 21.0 g mass. What is the ratio T1 to T2? A 1.0 B 1.6 C 2.1 D 2.6 11 A car of mass m moving at a constant speed v passes over a humpback bridge of radius of curvature r. Given that the car remains in contact with the road, what is the normal reaction force R experienced by the car when it is at the top of the bridge? A R = mg + mv2 r B R = mg - mv2 r C R = mv2 r - mg D R = mv2 r r v car

8 SAJC Prelims 2022 9749/01 [Turn Over 12 The acceleration of free fall on the surface of the Earth is 6 times its value on the surface of the Moon. The mean density of the Earth is 5 3 times the mean density of the Moon. If rE is the radius of the Earth and rM the radius of the Moon, what is the value of rE rM ? A 2.4 B 3.6 C 4.8 D 6.0 13 A car tyre, initially at 25 0 C, has been inflated to a pressure of 200 kPa as indicated by the pressure gauge. This means that the pressure in the tyre is 200 kPa above atmospheric pressure of 100 kPa. After driving on hot roads, the temperature of the air in the tyre is 500 C. What is the percentage increase in the pressure gauge reading? A 8.4 % B 12.5 % C 100 % D 150 % 14 A liquid is maintained at its boiling point by means of an electric heater. The constant rate at which the liquid boils away is measured for two different powers of the heater as shown. Power of heater Rate of loss of mass of liquid P1 m1 P2 m2 For each power of the heater, P1 or P2, the r