DHS 2023 H2 Phy P2

© DHS 2023 9749/02 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 PHYSICS Paper 2 Structured Questions Candidates answer on the Question Paper 9749/02 15 September 2023 2 hours READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and class at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the question paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 10 2 9 3 6 4 11 5 7 6 10 7 7 8 20 Total 80 This document consists of 21 printed pages and 1 blank page.

2 © DHS 2023 9749/02 Data speed of light in free space, c = 3.00 × 108 m s−1 permeability of free space, µo = 4π × 10−7 H m−1 permittivity of free space, εo = 8.85 × 10−12 F m−1 (1/(36π)) × 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

3 © DHS 2023 9749/02 [Turn over Formulae uniformly accelerated motion s = ut + at2 v2 = u 2 + 2as work done on/by a gas W = p∆V hydrostatic pressure p = ρgh gravitational potential φ = −Gm/r temperature T/K = T/oC + 273.15 pressure of an ideal gas p = mean translational kinetic energy of an ideal gas molecule E = displacement of particle in s.h.m. x = x 0 sin ωt velocity of particle in s.h.m. v = v0 cos ωt = ±ω electric current I = Anvq resistors in series R = R1 + R2 + . . . resistors in parallel 1/R = 1/R 1 + 1/R2 + . . . electric potential V = alternating current / voltage x = x0 sin ωt magnetic flux density due to a long straight wire B = magnetic flux density due to a flat circular coil B = magnetic flux density due to a long solenoid B = radioactive decay x = x0 exp(−λt) decay constant λ = 1 2 21 3 Nm cV <> kT2 3 2 2x xo − r Q oπε4 0 2 d Iµ π 0 2 N r Iµ 0nIµ 1 2 ln2 t

4 © DHS 2023 9749/02 Answer all questions in the spaces provided. 1 An experiment to determine the acceleration of free fall g is conducted by projecting a stone with speed u at an angle θ to the horizontal. The horizontal distance R travelled by the stone when it returns to the level of projection is measured. Air resistance is negligible. (a) In determining the speed of the stone, a student defines speed as “distance travelled per second”. Explain why this definition is incorrect. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. …………………………………………………………………………………………………….[2] (b) By expressing the time of flight of the stone T in terms of g, u and θ, show that R is given by the expression 22 sin cosuR g θθ= [3]

5 © DHS 2023 9749/02 [Turn over (c) The expression in (b) can be written as 2 sin2uR g θ= The experiment is conducted to obtain the maximum range R0. State the value of θ to obtain R0. θ = ........................................ o [1] (d) The values of u and R0 are 45.36 km h−1 and 16.3 m, with percentage uncertainties of 3% and 4% respectively. Calculate the value of g and present the answer together with its uncertainty. g = ................... ± ..................... m s −2 [4] [Total: 10]

6 © DHS 2023 9749/02 2 A lifting bag is a diving equipment which is used to lift heavy objects underwater by means of the bag’s buoyancy. To retrieve a submerged cannon of mass 800 kg and density 8000 kg m−3 resting on the seabed back to the surface, an uninflated lifting bag of negligible mass and volume was attached to the cannon by a diver. The density of seawater is 1050 kg m−3. (a) Explain the origin of upthrust. …………………………………………………………………………………….……………… ……………………………………………………………………………………..………...…… ………………………………………………………………………………..…………….……[1] (b) Show that upthrust acting on the cannon is 1030 N. [1] Air was suddenly released into the lifting bag, causing it to inflate and the cannon to be lifted off the seabed. The variation with time of the momentum of the cannon is shown in Fig. 2.1. Fig. 2.1 momentum / kg m s −1 time / s 200 400 600 800 0 5.00 15.0 25.0 10.0 20.0 30.0 35.0

7 © DHS 2023 9749/02 [Turn over (c) State Newton’s second law of motion. ………………………………………………………………………………………………………. ..…………………………………………………………………………………………………….. …………………………………………………………………………………………………… [2] (d) Explain why the momentum of the cannon increases non-linearly as shown in Fig. 2.1. ………………………………………………………………………………………………………. ..………………………………………………………………………………………….………….. ………………………………………………………………………………………………………. ..………………………………………………………………………………………….………….. …………………………………………………………………………………………………… [2] (e) Using Fig. 2.1, estimate the volume of air that was released into the lifting bag. volume of air = ………………………………. m3 [3] [Total: 9]

8 © DHS 2023 9749/02 3 A horizontal flat plate is free to rotate about a vertical axis through its centre, as shown in Fig. 3.1. A small mass M is placed on the plate, a distance d from the axis of rotation. The speed of rotation of the plate is gradually increased from zero until the mass is seen to slide off the plate. The maximum frictional force F between the plate and the mass is given by the expression F = 0.72W where W is the weight of the mass M. The distance d is 35 cm. (a) Determine the maximum number of revolutions of the plate per minute for the mass M to remain on the plate. Explain your working. number of revolutions per minute = .................................. [4] Fig. 3.1

9 © DHS 2023 9749/02 [Turn over (b) The plate is covered, when stationary, with mud. Suggest and explain whether mud near the edge of the plate or near the centre will first leave the plate as the angular speed of the plate is slowly increased. …..…………………………………………………………………………………………………... …..…………………………………………………………………………………………………... …..…………………………………………………………………………………………………... …..…………………………………………………………………………………………………... …..…………………………………………………………………………………………………... …………………………………………………………………………………………………… [2] [Total: 6]

10 © DHS 2023 9749/02 4 Galileo used a simple pendulum to take the time for objects to roll down an inclined plane. Fig. 4.1 shows a simple pendulum. Fig. 4.1 (not to scale) A simple pendulum oscillates with simple harmonic motion. (a) State what is meant by simple harmonic motion. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. …………………………………………………………………………………………………… [2]