2024 CJC H1.Phy.PRELIM P2

CANDIDATE NAME CLASS 2T PHYSICS 8867/2 Paper 2 Structured Questions 23 August 2024 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. Section A Answer all questions. Section B Answer any one question. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 23 printed pages and 1 blank page. [Turn over FOR EXAMINER’S USE DIFFICULTY L1 L2 L3 Q1 / 7 Q2 / 7 Q3 / 7 Q4 / 8 Q5 / 8 Q6 / 7 Q7 / 16 Q8 / 20 Q9 / 20 PAPER 2 (WEIGHTAGE: 67%) / 80 PAPER 1 (WEIGHTAGE: 33%) / 30 TOTAL % Catholic Junior College JC2 Preliminary Examination Higher 1

2 Data speed of light in free space, c = 3.00  108 m s1 elementary charge, e = 1.60  1019 C 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 the Avogadro constant, NA = 6.02  1023 mol1 gravitational constant, G = 6.67  1011 N m2 kg2 acceleration of free fall, g = 9.81 m s2 Formulae uniformly accelerated motion, s = ut + 1 2 at2 v2 = u2 + 2as resistors in series, R = R1 + R2 + . . . resistors in parallel, 1/R = 1/R1 + 1/R2 + . . .

3 [Turn over Section A Answer ALL questions in this section. 1 (a) A student writes down the following equation to describe the forces acting on a sphere falling under gravity through a medium of liquid,   2 3 L 46 3rv r g     whereby r is the radius of the sphere, v the velocity, g the acceleration of free fall,  the coefficient of viscosity of the liquid with units: kg m−1 s−1,  and L the densities of the sphere and the liquid respectively. By checking the homogeneity of the equation, deduce whether the equation is correct. [2] (b) The drag force F experienced by a steel sphere of radius r dropping at speed v through a liquid is given by 2 2F Br v  where B is a constant. A student obtained the following set of data for a steel sphere dropping through a fluid. F = (8.0  0.1) mN r = (3.0  0.1) cm  = (1.00  0.01)  103 kg m−3 v = (24  1) cm s−1 (i) Random errors are associated with the measurement of the diameter of the steel sphere. 1. Explain what is meant by a random error. ..…………………………………………… .…………………………………... ……. .…... ……………………………………… ……..... ………….…….…….… ....... [1]

4 2. Hence, explain how such a random error can be minimized in this experiment. ...………………………………………………………………………………... ……. .…...……………………………………… ……..... ………….…….…….… ....... [1] (ii) Using the data given, determine the value of B together with its associated uncertainty. B = …... … … .….. … ±.… …... ...… ..... [3] [Total: 7]

5 [Turn over 2 A ball was kicked over a wall of height h as shown with a velocity 16.4 m s-1 at an angle of 50° above the horizontal. At the highest point of the trajectory, the ball managed to just go over the wall. It landed into a pit 2.0 m deep. Fig. 2.1 (a) Calculate the height h of the wall. h = …... …… … …… … …. .… ….. .. m [2] (b) Calculate the time of flight of the ball when it just hits the pit. time = …... ……… …… ….. … …. .… ... s [3] 16.4 m s-1 50° 2.0 m h ball wall pit

6 (c) Calculate the vertical velocity of the ball just before it hits the pit. vertical velocity = …... ……… ….. … …. .… ... m s-1 [2] [Total: 7]

7 [Turn over 3 (a) Three co-planar forces act on a body that is in equilibrium. (i) By drawing a vector diagram, d escribe how a vector diagram can be used to represent these forces. ………………………………………………………………………………………... ……. ………………………………………………………………………………………... ……. ………………………………………………… …….....………….…….…….…....... [2] (ii) Explain why the vector triangle cannot be used to show that a body is in rotational equilibrium. ………………………………………………………………………………………... ……. ………………………………………………………………………………………... ……. ………………………………………………… ……..... ………….…….…….… ....... [1] (b) Fig. 3.1 shows a uniform thin rod of weight W = 1000 N, being towed at angle of 30 to the ground by a force T. It is moving at a constant horizontal velocity. Fig. 3.1 (i) On Fig. 3.1, indicate the direction of the reaction force R acting on the rod by th e ground at point A. [1] W 30  A T ground rod

8 (ii) The force T is applied on the rod at an angle  of 46 with respect to the horizontal. Determine T. T = …... … ..….. …… ……. ...… ..... N [3] [Total: 7]

9 [Turn over 4 (a) State Newton’s law of gravitation. ………….…………………..……………………………………………………………………… ………….…………………..……………………………………………………………………… ………………………………………………………………………….………………….….. [2] (b) Two stars of mass M and 2M, a distance of 3R apart, rotate in circles about their common centre of mass O. They form a binary star system as shown in Fig. 4.1. Fig. 4.1 The period of this binary star system is 3.42  105 s. The value of M is 3.14  1030 kg. (i) Express the gravitational force of attraction between the two stars in terms of R. [1] (ii) Calculate the angular speed for each star. angular speed = …... … ..….. …… ....… ..... rad s-1 [2] O M 2M R R

10 (iii) Determine the distance R. R = …... … ..….. … ……… ....… ..... m [3] [Total: 8]