DHS 2022 JC1 Promos Physics (Paper 2)

1 © DHS 2022 9749 [Turn over Name: Index Number: Class: DUNMAN HIGH SCHOOL Promotional Examination Year 5 H2 PHYSICS Section B Structured Questions 9749 27 September 2022 1 hour 30 minutes READ THESE INSTRUCTIONS FIRST Write your class, index number and name 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 Section A MCQ 15 Section B 1 6 2 6 3 7 4 7 5 6 6 6 7 4 8 10 9 8 s.f. -1 Total 75 This document consists of 19 printed pages and 1 blank page.

2 © DHS 2022 9749 [Turn over Data speed of light in free space, c = 3.00 × 108 m s−1 permeability of free space, o = 4 × 10−7 H m−1 permittivity of free space, o = 8.85 × 10−12 F m−1 = (1/(36)) × 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 2022 9749 [Turn over Formulae uniformly accelerated motion, s = ut + 1 2 at2 v2 = u2 + 2as work done on/by a gas, W = pV hydrostatic pressure, p = gh gravitational potential,  = −Gm/r temperature, T/K = T/oC + 273.15 pressure of an ideal gas, p = 21 3 Nm cV  mean translational kinetic energy of an ideal gas molecule, E = kT2 3 displacement of particle in s.h.m., x = x0 sin t velocity of particle in s.h.m., v = v0 cos t =  22 xxo − electric current, I = Anvq resistors in series, R = R1 + R2 + . . . resistors in parallel, 1/R = 1/R1 + 1/R2 + . . . electric potential, V = r Q o4 alternating current / voltage, x = x0 sin t magnetic flux density due to a long straight wire, B = 0 2 d I  magnetic flux denxity due to a flat circular coil, B = 0 2 N r I magnetic flux density due to a long solenoid, B = 0nI radioactive decay, x = x0 exp(−t) decay constant,  = 1 2 ln2 t

4 © DHS 2022 9749/02 [Turn over Answer all the questions. 1 (a) Make reasonable estimates of the following quantities. (i) the frequency of an audible sound wave, frequency = ....................................... Hz [1] (ii) the wavelength of ultraviolet radiation. wavelength = ....................................... nm [1] (b) State what is meant by a vector quantity. ……………………………………………………………………………………………...……….. ………………………………………………………………………………………………….... [1] (c) An aircraft is travelling towards the west. Fig. 1.1 shows the velocities of the aircraft in still air and of the wind. (i) On Fig. 1.1, draw an arrow, labelled R, in the direction of the resultant velocity of the aircraft. [1] (ii) Determine the magnitude of the resultant velocity of the aircraft. velocity = ....................................... m s−1 [2] [Total: 6] Fig. 1.1

5 © DHS 2022 9749 [Turn over 2 In the absence of air resistance, a projectile is launched at point O with an initial speed u at an angle  to the horizontal. OA is the maximum horizontal distance that can be reached. The path of the projectile is shown in Fig. 2.1. (a) State the angle  that will give the maximum horizontal distance of the projectile.  = ...................................... o [1] (b) The maximum horizontal distance OA is 4.00 m. Calculate the initial speed u. u = ...................................... m s−1 [3] (c) Calculate the maximum height reached by the projectile. maximum height = ...................................... m [1] (d) In practice, air resistance cannot be ignored. On Fig. 2.1, sketch the path of the projectile when air resistance is not negligible. [1] [Total: 6] A u O  4.00 m Fig. 2.1

6 © DHS 2022 9749 [Turn over 3 A jet of water hits a vertical wall at right angles, as shown in Fig. 3.1. The water hits the vertical wall with a velocity of 5.0 m s−1 in a horizontal direction. The cross- sectional area of the jet is 1.5 × 10−4 m2. The density of the water is 1.0 × 103 kg m−3. The water runs down the wall after hitting it. (a) Show that, over a time of 1.6 s, the mass of water hitting the wall is 1.2 kg. [2] (b) Calculate (i) the decrease in the horizontal momentum of the mass of water in (a) due to hitting the wall, decrease in momentum = .................................................... N s [1] (ii) the magnitude of the horizontal force exerted on the water by the wall. force = ...................................................... N [1]

7 © DHS 2022 9749 [Turn over (c) State and explain the magnitude of the horizontal force exerted on the wall by the water. ……………………………………………………………………………………………..………... ………………………………………………………………………………………………….... [1] (d) Calculate the pressure exerted on the wall by the water. pressure = .................................................... Pa [1] (e) State how the principle of conservation of momentum applies for the interaction between the water and the wall. ……………………………………………………………………………………………..………... ………………………………………………………………………………………………….... [1] [Total: 7]

8 © DHS 2022 9749 [Turn over 4 (a) State the conditions for an object to be in equilibrium. ……………………………………………………………………………………………..………... ……………………………………………………………………………………………..………... ……………………………………………………………………………………………..………... ………………………………………………………………………………………………….... [2] (b) A uniform ladder of length 12.0 m and mass 40.0 kg rests on a wall. The lower end of the ladder is 6.00 m from the wall as shown in Fig. 4.1. The wall is smooth while the ground is rough. A man of mass 72.0 kg starts to climb up the ladder. He stops when he is three-quarters way up the ladder. (i) Calculate the normal contact force 1. by the wall on the ladder, normal contact force = ...................................................... N [2] Fig. 4.1 12.0 m 6.00 m

9 © DHS 2022 9749 [Turn over 2. by the ground on the ladder. normal contact force = ...................................................... N [1] (ii) Hence determine the magnitude of the total reaction force the ground exerts on the ladder. total reaction force = ...................................................... N [1] (iii) On Fig 4.1, draw an arrow, labelled R, to show the direction of the total reaction force found in (b)(ii). [1] [Total: 7]

10 © DHS 2022 9749 [Turn over 5 (a) Show, using the equations of motion and the definition of work done, the kinetic energy EK of an object of mass m travelling with speed v is 2 K 1 2E mv= . [2] (b) A child of weight 330 N is at point X at the top of a slide. The