2022 H2 CJC Physics Promo Paper 2 QP

[Turn over CANDIDATE NAME CLASS 1T PHYSICS 9749/2 Paper 2: Structured Questions 30 September 2022 2 hours Candidates answer on the Question Paper No Additional Materials are required READ THESE INSTRUCTIONS FIRST Write your name and class on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 20 printed pages and 0 blank page. FOR EXAMINER’S USE DIFFICULTY L1 L2 L3 Q1 / 11 Q2 / 10 Q3 / 10 Q4 / 12 Q5 / 9 Q6 / 15 Q7 / 13 PAPER 2 / 80 Catholic Junior College JC1 Promotional Examinations Higher 2

2 DATA speed of light in free space c = 3.00 x 108 m s-1 permeability of free space 0 = 4 x 10-7 H m-1 permittivity of free space 0 = 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 mol-1 gravitational constant G = 6.67 x 10-11 N m2 kg-2 acceleration of free fall g = 9.81 m s-2

3 [Turn over Formulae uniformly accelerated motion s = u t + ½ a t2 v2 = u2 + 2as work done on / by a gas W = p V hydrostatic pressure p = gh gravitational potential  = - Gm r temperature T / K = T / ˚C + 273.15 pressure of an ideal gas p = 1 3 Nm V 〈c2〉 mean translational kinetic energy of an ideal gas molecule E = 3 2 kT displacement of particle in s.h.m. x = x0 sin t velocity of particle in s.h.m. v = v0 cos t = 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 = Q 4πεor alternating current / voltage x = x0 sin t magnetic flux density due to a long straight wire B = μoI 2πd magnetic flux density due to a flat circular coil B = μoNI 2r magnetic flux density due to a long solenoid B = μonI radioactive decay x = x0 exp(-t) decay constant λ = 1 2 ln 2 t

4 Answer all the questions in the spaces provided. 1 (a) A ball of mass 0.50 kg leaves the edge of a table with a horizontal velocity v, as shown in Fig. 1.1. Fig. 1.1 The height of the table is 1.25 m. The ball travels a distance of 1.50 m horizontally before hitting the floor. Air resistance is negligible. For the ball, (i) show that the horizontal velocity v is 3.0 m s-1, [2] ball table path of ball v 1.25 m 1.5 m floor

5 [Turn over (ii) calculate the velocity just as it hits the floor. magnitude of velocity = ………...……..……………. m s -1 direction of velocity = ………………………………………. [3] (iii) Using the floor as reference where the potential energy of the ball is zero, calculate the kinetic energy and potential energy of the ball at the top of the table. kinetic energy = ………...….…..……………. …J potential energy = ………...….…..……………. …J [2]

6 (b) The horizontal distance, along the floor, from the bottom of the table is x. Fig. 1.2 shows the variation with x of the potential energy Ep of the ball. On Fig 1.2, sketch the variation with x of the kinetic energy Ek of the ball. Fig. 1.2 [2] (c) On Fig 1.1, draw the path of the ball if air resistance was not negligible. [2] x / m 1.5 0 Energy / J EP 0.75

7 [Turn over 2 (a) State the principle of moments. …………………………………………………………………………………………… .. ………………………………………………………………………………………… ….. [1] (b) In a bicycle shop, two wheels hang from a horizontal uniform rod AC, as shown in Fig. 2.1. Fig. 2.1 (not to scale) The rod has weight 19 N and is freely hinged to a wall at end A. The other end C of the rod is attached by a vertical elastic cord to the ceiling. The centre of gravity of the rod is at point B. The weight of each wheel is W and the tension in the cord is 22 N. (i) By taking moments about end A, show that the weight W of each wheel is 14 N. [2] (ii) Determine the magnitude and the direction of the force acting on the rod at end A. magnitude = ….…..….……………. N direction = ….….…..….……………. [2]

8 (c) The unstretched length of the cord in (b) is 0.25 m. The variation with length L of the tension F in the cord is shown in Fig. 2.2. Fig. 2.2 (i) State and explain whether Fig. 2.2 suggests that the cord obeys Hooke’s law. ……………………………………………………………………………………… ……………………………………………………………………………………… [2] (ii) Calculate the spring constant k of the cord. k = ….…..….……………. N m -1 [2] (iii) On Fig. 2.2, shade the area that represents the work done to extend the cord when the tension is increased from F = 0 to F = 40 N. [1]

9 [Turn over 3 (a) (i) Define gravitational potential at a point. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [2] (ii) Use your answer in (i) to explain why the gravitational potential near an isolated mass is always negative. ………………………………………………………………………………… …. …………………………………………………………………………………… . …………………………………………………………………………………… …………………………………………………………………………………… . [2] (b) A rocket is launched from the surface of a planet and moves along a radial path, as shown in Fig. 3.1. Fig.3.1 The planet may be considered to be an isolated sphere of radius R with all of its mass M concentrated at its centre. Point A is a distance R from the surface of the planet. Point B is a distance 4R from the surface. (i) Show that the difference in gravitational potential ∆ϕ between points A and B is given by the expression GM R 3 10  where G is the gravitational constant. [1]

10 (ii) The rocket motor is switched off at point A. During the journey from A to B, the rocket has a constant mass of 4.7 × 10 4 kg and its kinetic energy changes from 1.70 TJ to 0.88 TJ. For the planet, the product GM is 4.0 × 1014 N m2 kg–1. It may be assumed that resistive forces to the motion of the rocket are negligible. Use the expression in (b)(i) to determine the distance from A to B. distance = ……………………… m [3] (c) A spherical planet has mass 6.00 × 1024 kg and radius 6.40 × 106 m. The planet may be assumed to be isolated in space with it