Physical Sciences Grade 12 Northern Cape Mock 2021 QP (Eng)

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 1 September 2021 ————————————————————— DEPARTMENT OF EDUCATION ————————————————————— DEPARTEMENT VAN ONDERWYS ————————————————————— LEFAPHA LA THUTO ————————————————————— ISEBE LEZEMFUNDO ————————————————————— PROVINCIAL PREPARATORY EXAMINATION GRADE 12 PHYSICAL SCIENCES: PHYSICS (P1) SEPTEMBER 2021 MARKS: 150 TIME: 3 hours This question paper consists of 15 pages and 3 data sheets. Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 2 September 2021 INSTRUCTIONS AND INFORMATION 1. Write your NAME in the appropriate spaces on the ANSWER BOOK. 2. Answer ALL the questions in the ANSWER BOOK. 3. You may use a non-programmable calculator. 4. You may use appropriate mathematical instruments. 5. Number the answers correctly according to the numbering system used in this question paper. 6. YOU ARE ADVISED TO USE THE ATTACHED DATA SHEETS. 7. Give brief motivations, discussions, et cetera where required. 8. Start EACH question on a NEW page. 9. Show the formulae and substitutions in ALL calculations. 10. Leave ONE line between two sub-questions, for example between QUESTION 2.1 and QUESTION 2.2. 11. Round off your final numerical answers to a minimum of TWO decimal places. 12 Write neatly and legibly. Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 3 September 2021 QUESTION 1: MULTIPLE-CHOICE QUESTIONS Various possible options are provided as answers to the following questions. Choose the answer and write only the letter (A–D) next to the question number (1.1 to 1.10) in the ANSWER BOOK, for example 1.11 D. 1.1 A box of mass m is pulled over a rough surface by a horizontal force ⃗F. Which ONE of the forces below is the contact force exerted by the surface on the box? A Normal force B Kinetic frictional force. C Weight of the box. D Resultant of the normal force and the kinetic frictional force. (2) 1.2 A tennis ball which is thrown horizontally, hits a wall and bounces back horizontally. The vectors ⃗pi and ⃗pf shown below, represent the linear momentum of the ball just before and after the ball hits the wall. ⃗pi ⃗pf Which ONE of the following vectors represents the change in linear momentum of the tennis ball? A B C D (2) Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 4 September 2021 1.3 Man S, with a mass of 80 kg, pushes man T with a mass of 60 kg, with a horizontal force of 80 N. What is the magnitude of the force which man T applies on man S? A 80 N B 0N C 20 N D 60 N (2) 1.4 A block of mass m is placed on a smooth inclined plane of inclination θ with the horizontal. What is the magnitude of the normal force exerted by the surface on the block? θ A mg B mg cos θ C mg sin θ D mg tan θ (2) 1.5 A ball hits a floor and rebounds after an inelastic collision. Which ONE of the statements below is TRUE for this collision? A The total kinetic energy before the collision is equal to total kinetic energy after the collision. B The linear momentum of the ball before the collision is equal to the linear momentum of the ball after the collision. C Total linear momentum of the ball and the Earth is conserved. D The mechanical energy of the ball remains the same during the (2) collision. Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 5 September 2021 1.6 An observer moves towards a stationary source of sound. Which ONE of the statements below regarding the sound heard by the observer compared to the sound emitted by the source, is correct? A The wavelength of sound has decreased. B The speed of sound relative to the air has decreased. C The wavelength of sound has increased. D The frequency of the sound has increased. (2) 1.7 Two identical isolated spheres P and Q have charges of +8 nC and -8 nC respectively. A third identical sphere R is initially uncharged (neutral). Sphere R is moved and touches sphere P. Sphere R is now moved so that it touches Q after which the two spheres are separated again. What is the final charge on sphere R? P Q QP = +8 nC QQ= -8 nC R QR= 0 nC A +4 nC. B -4 nC. C +2 nC. (2) D -2 nC. Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 6 September 2021 1.8 The circuit diagram below shows four identical bulbs M, N, P and Q connected to a battery. The power dissipated in bulb M is 60 W. The resistance of the connecting wires may be ignored. M N P Q The power dissipated in bulb Q is… A 0W B 15 W C 30 W (2) D 60 W 1.9 A maximum emf (ε) is induced in the coil of a generator. The speed of rotation of the coil is now doubled. What is the maximum emf which is now induced in the generator? A 4ε B 2ε C ε D 1 ε (2) 2 1.10 Light of a certain frequency is shone onto the metal plate of a photo cell Which ONE of the following factors determine whether electrons are ejected from the plate? A The intensity of the light B The area of the plate. C The material of which the plate is made. (2) D How long the plate is exposed to the light. [20] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 7 September 2021 QUESTION 2 (Start on a new page.) A block A of mass 4 kg is placed on a table and connected by a massless string passing over a massless, frictionless pulley, to block B of mass 5 kg as shown in diagram below. The two blocks are at rest. 2.1 State Newton’s first law of motion in words (2) Calculate the magnitude of the maximum static frictional force acting on 2.2 (4) block A. A force of 15 N downwards is now applied to block B as shown below. The magnitude of the kinetic frictional force acting on block A is 46 N. F=15 N 2.3.1 Draw a labelled free-body diagram for block B. (3) 2.3.2 Calculate the magnitude of the acceleration of block B. (5) 2.4 If a force of 5 N to the left is now applied to block A. How will the acceleration of the system compare to that calculated in QUESTION 2.3.2? Choose from GREATER THAN, SMALLER THAN or EQUAL TO. (2) Give a reason for the answer. [16] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 8 September 2021 QUESTION 3 (Start on a new page.) A ball is dropped from a height of 19.6 m above the ground. It rebounds from the ground, reaching its original height h. Ignore the contact time of the ball with the ground and the effects of air resistance. h=19,6 m v Ground 3.1 What is meant by a projectile in Physics? (2) 3.2 What is the total displacement of the ball? (1) 3.3 Use equations of motion ONLY to calculate the: 3.3.1 Time taken by the ball to raise up the same height. (3) 3.3.2 Velocity with which the ball leaves the ground after rebounding. (3) 3.4 Sketch the position-time graph for the complete motion of the ball. Show the following on the graph:  The time taken by the ball to reach the ground  The time taken by the ball to reach the starting point  The initial and final position of the ball (3) [12] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 9 September 2021 QUESTION 4 (Start on a new page.) ABC is a frictionless track. A is a point 6 m above the ground. Blocks P and Q of mass 4 kg and 6 kg respectively, and a spring of negligible mass clamped together so that the fully compress spring is aligned between blocks P and Q. At position A the system moves as a whole at a speed of 4,5 m·s -1. The system slides down and reaches point B at the bottom of the ramp as shown in diagram below. Ignore air friction. -1 4,5 m·s P Q A 6m P Q B C 4.1 State the law of conservation of mechanical energy in words. (2) 4.2 Use the law of conservation of mechanical energy to calculate the speed of (4) the blocks at the bottom of the ramp. At the bottom of the ramp the clamp is released (by remote control so that the motion of the system as a whole is not affected in any way).As the spring expands (stretches), the blocks move apart. The speed of block Q is now increased 10 %. 4.3 Use the law of conservation of linear momentum to calculate the velocity of block P after the spring has been expanded. (4) 4.4 Calculate the magnitude of the impulse which block Q exerts on block P. (3) [13] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 10 September 2021 QUESTION 5 (Start on a new page.) A diver of mass 80 kg, steps off a diving board at point A, 4,0 m above the level of the water of a swimming pool. The diver enters the water at point B and comes to rest at point C. While the diver falls through the air, an average frictional force of magnitude 172 N acts on the diver. The total work done on the diver while he moves from A to C is -6240 J. A h=4m B d C 5.1 State the work-energy theorem in words. (2) 5.2 Use the work-energy theorem to calculate the speed of the diver at point B. (4) 5.3 Is the mechanical energy of the diver conserved? Choose from YES or NO. Give a reason for the answer. (2) 5.4 Using energy principles ONLY, calculate the distance from B to C. (4) [12] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 11 September 2021 QUESTION 6 (Start on a new page.) The driver of a car pulls over to the side of a straight road and stops when he hears the siren of an approaching fire truck. As the fire truck approaches, the person hears a frequency of 460 Hz; as the fire truck moves away, the person hears a frequency of 410 Hz. Consider the speed of sound in air as 340 m∙s-1. 6.1 State the Doppler effect in words. (2) 6.2 Does the stationary person detect a longer or shorter wavelength as the fire truck moves away? Explain your answer. (3) 6.3 Calculate the frequency of the sound of the siren. (6) 6.4 A study of spectral lines obtained from various stars can provide valuable information about the movement of the stars. The two diagrams below represents different spectral lines of an element. Diagram 1 represents the spectrum of the element in a laboratory on Earth. Diagram 2 represents the spectrum of the same element from a distant star. Blue Red Diagram 1 Blue Red Diagram 2 Is the star moving towards or away from the Earth? Explain the answers by referring to the shift in the spectral lines. (3) 6.5 Write down ONE application of Doppler effect. (1) [15] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 12 September 2021 QUESTION 7 (Start on a new page.) The diagram below shows a small sphere X from which 938 electrons were removed and two points A and B at different distances from the sphere X. 0,01 m 0,03 m A X B 7.1 What is the nature of the charge on sphere X? Choose from POSITIVE or (1) NEGATIVE. 7.2 Calculate the magnitude of the charge on sphere X. (3) 7.3 Define electric field at a point in words (2) 7.4 Draw the electric field pattern around sphere X. (2) 7.5 At what point, A or B, is the magnitude of the electric field due to the charged sphere X greater? Explain the answer. (3) 7.6 A negative point charge Y with charge -2,8 x 10-16 C is NOW placed at point B and a point charge Z with charge +3,2 x 10-16 C is placed at point A. 7.6.1 State Coulomb’s law in words. (2) 7.6.2 Calculate the net electrostatic force on sphere X. (5) [18] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 13 September 2021 QUESTION 8 (Start on a new page.) Three IDENTICAL lightbulbs A, B and C each with a resistance of 8 Ω are connected to a battery with emf 12 V and unknown internal resistance, as shown in circuit diagram below. The resistance of the connecting wires and the ammeter may be ignored. A B C S V A r 12 V Switch S is closed. The ammeter reading is 2 A. 8.1 Define the term electrical power in words. (2) 8.2 Calculate the: 8.2.1 Reading on the voltmeter. (5) 8.2.2 Internal resistance of the battery. (3) 8.3 Compare the brightness of the lightbulbs A, B and C. Justify the answer. (4) 8.4 Switch S is now opened. How would the voltmeter reading change? Choose from INCREASES, DECREASES or REMAINS THE SAME. Explain the answer. (4) [18] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 14 September 2021 QUESTION 9 (Start on a new page.) The simplified diagrams below represent two electrical machines A and B. N S A B 9.1 Classify the above electrical machines into a DC motor and generator. (4) Give a reason for the answer in each case. 9.2 What type of generator (AC or DC) is represented in the simplified (2) diagrams above? Give a reason for your answer. 9.3 Name the principle on which generators work. (1) 9.4 Which ONE of the following graphs (R or S) represents the voltage (1) output of the generator identified in 9.2 above? Voltage (V) Time (s) Voltage (V) Time (s) Graph R Graph S 9.5 An AC generator, producing a maximum voltage of 311,13 V, is connected to a heater of resistance 40 Ω. Calculate the average power dissipated by the heater. (5) [13] Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 15 September 2021 QUESTION 10 (Start on a new page.) Photoelectric effect can be studied with a device like the one shown below. Light of frequency 6,2 ×1014 Hz shines on a sodium plate which has a work function of 3,648 ×10-19 J , ejecting electrons, which are then attracted to a positively charged “collector” plate. The result is an electric current that can be measured with an ammeter. Incoming light Collector Sodium plate A V Sliding contact + - + - 10.1 Define the term work function in words. (2) 10.2 Calculate the maximum wavelength needed to release electrons from the sodium plate. (3) 10.3 Calculate the maximum speed of the electrons ejected (photoelectrons). (4) 10.4 To determine the effect of the intensity of a radiation on the photo-electric current, radiations of the same frequency with different intensities is incident on the sodium plate. The following graphs of current (I) versus potential difference (V) were obtained. I (A) B A 0 V (V) 10.4.1 Which ONE of the curves corresponds to a radiation of greater intensity? Explain the answer. (3) 10.4.2 How does the maximum kinetic energy of the ejected electrons by radiation A compare to the maximum kinetic energy of the ejected electrons by radiation B. Choose from GREATER THAN, SMALLER THAN or EQUAL TO. (1) [13] GRAND TOTAL: 150 Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 1 September 2021 DATA FOR PHYSICAL SCIENCES GRADE 12 PAPER 1 (PHYSICS) GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 12 VRAESTEL 1 (FISIKA) TABLE 1: PHYSICAL CONSTANTS/TABEL 1: FISIESE KONSTANTES Copyright reserved

Downloaded from hlayiso.com Physical Sciences P1/Gr 12 22 September 2021 TABLE 2: FORMULAE/TABEL 2: FORMULES MOTION/BEWEGING v f  v i  a t Δx  v i Δt  21 at 2 or/of Δy  v i Δt  21 at 2  v  vf   v  vf  v f  v i  2ax or/of v f  v i  2ay 2 2 2 2 Δx   i  Δt or/of Δy   i  Δt  2   2  FORCE/KRAG Fnet  ma p mv   sN max fs fk   k N Fnet t  p w  mg p  mv f – mvi m1m 2 m1m 2 M M FG or/of FG g G or/of g G 2 d2 r2 d2 r WORK, ENERGY AND POWER/ARBEID, ENERGIE EN DRYWING W  Fx cos  U  mgh or/of EP  mgh Wnet  K or/of Wnet  Ek 1 1 K  mv2 or/of E k  mv 2 2 2 K  K f  K i or/of Ek  Ekf  Eki W Wnc  K  U or/of Wnc  Ek  Ep P t Pave  Fv ave / Pgemid  Fv gemid WAVES, SOUND AND LIGHT/GOLWE, KLANK EN LIG 1 vf T f v  vL v  vL c fL  fs fL  fb E  hf or/of E h v  vs v  vb  E  Wo  Ek(max) or/of E  Wo  K max where/waar 1 1 E  hf and/en W0  hf0 and/en E k (max)  mvmax 2 or/of K max  mvmax 2 2 2 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1/Grade 12 3 September 2021 ELECTROSTATICS/ELEKTROSTATIKA kQ1Q 2 kQ F E r2 r2 W F V E q q Q Q n or/of n e qe ELECTRIC CIRCUITS/ELEKTRIESE STROOMBANE V emf ( ε )  I(R + r) R I emk ( ε )  I(R + r) R s  R1  R 2  ... 1 1 1 q I t    ... R p R1 R 2 W W  Vq P Δt W  VI  t P  VI W  I2R  t P  I 2R V 2 Δt W  V2 R P R ALTERNATING CURRENT/WISSELSTROOM I I Pave  Vrms Irms / Pgemiddeld  Vwgk I wgk I rms  max / I wgk  maks 2 2 Pave  Irms 2 R / Pgemiddeld  I 2wgkR V V 2 2 Vwgk Vrms  max / Vwgk  maks P  Vrms / Pgemiddeld  2 2 ave R R Copyright reserved