SENIOR CERTIFICATE EXAMINATION

Transcription

1 SENIOR ERTIFITE EXMINTION PHYSIL SIENES P1 PHYSIS 015 MRKS: 150 TIME: 3 hours This question paper consists of 16 pages and 3 data sheets.

2 Physical Sciences/P1 E/015 INSTRUTIONS N INFORMTION Write your centre number and examination number in the appropriate space in the NSWER OOK. This question paper consists of ELEVEN questions. nswer LL the questions in the NSWER OOK. Start EH question on a NEW page in the NSWER OOK. Number the answers correctly according to the numbering system used in this question paper. Leave ONE line between two subquestions, for example between QUESTION.1 and QUESTION.. You may use a non-programmable calculator. You may use appropriate mathematical instruments. You are advised to use the attached T SHEETS. Show LL formulae and substitutions in LL calculations. Round off your FINL numerical answers to a minimum of TWO decimal places. Give brief motivations, discussions, et cetera where required. Write neatly and legibly.

3 Physical Sciences/P1 3 E/015 QUESTION 1: MULTIPLE-HOIE QUESTIONS Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. hoose the answer and write only the letter ( ) next to the question number ( ) in the NSWER OOK, for example 1.11 E. 1.1 horizontal force F is applied to a crate, causing it to move over a rough, horizontal surface as shown below. crate F The kinetic frictional force between the crate and the surface on which it is moving depends on the applied force F. the surface area of the crate in contact with the floor. how fast the crate moves on the surface. the upward force exerted by the surface on the crate. () 1. n object is placed on a bathroom scale in a lift which is stationary on the third floor of a building. The reading on the scale will be greatest when the lift... accelerates downward. accelerates upward. moves upward at constant speed. moves downward at constant speed. () 1.3 ball is thrown vertically upwards into the air. Ignore the effects of friction. The NET FORE acting on the ball when the ball is at its highest point is... zero. equal to the weight of the ball. Iess than the weight of the ball. greater than the weight of the ball. ()

4 Physical Sciences/P1 4 E/ uring a collision an inflated air bag in a car decreases the net force that would have acted on the driver of the car. This is because the time interval over which the net force acts on the driver for the same momentum change. is zero decreases increases remains constant () 1.5 n object moving horizontally at a constant velocity suddenly encounters a rough horizontal surface. The object continues to move over this rough surface. Which ONE of the following statements is ORRET? The net work done on the object during the motion over the rough surface is zero. positive. negative. constant. () 1.6 The hooter of a car emits sound of constant frequency as the car moves away from a stationary listener. Which ONE of the following properties of the sound heard by the listener will NOT change? Velocity Frequency oth wavelength and frequency oth frequency and loudness ()

5 Physical Sciences/P1 5 E/ Two identical positively charged spheres, which are free to move, are placed near each other on a frictionless surface. Which ONE of the following ORRETLY describes the motion of the two spheres? They move away from each other with increasing acceleration. They move away from each other with decreasing acceleration. They move away from each other with constant acceleration. They move away from each other with zero acceleration. () 1.8 The diagram below shows a cell of emf (ε ), and two resistors, R 1 and R, in series, with R 1 < R. The cell has negligible internal resistance and the voltmeters have very high resistances. ε R 1 R V 1 V Which ONE of the following is ORRET? V 1 = V = ε V 1 > V V R 1 1 V = R V R 1 1 V > R () 1.9 generator operates at 80 Hz. The number of times the output voltage reaches a maximum in 1 second is ()

6 Physical Sciences/P1 6 E/ Light of a certain frequency is incident on a metal surface and photoelectrons are emitted from the surface. If the INTENSITY of the same light is increased, the... kinetic energy of the emitted photoelectrons increases. kinetic energy of the emitted photoelectrons decreases. number of photoelectrons emitted per second increases. number of photoelectrons emitted per second decreases. () [0]

7 Physical Sciences/P1 7 E/015 QUESTION (Start on a new page.) 5 kg block, resting on a rough horizontal table, is connected by a light inextensible string passing over a light frictionless pulley to another block of mass kg. The kg block hangs vertically as shown in the diagram below. force of 60 N is applied to the 5 kg block at an angle of 10 o to the horizontal, causing the block to accelerate to the left. 60 N 10 o 5 kg kg The coefficient of kinetic friction between the 5 kg block and the surface of the table is 0,5. Ignore the effects of air friction..1 raw a labelled free-body diagram showing LL the forces acting on the 5 kg block. (5). alculate the magnitude of the:..1 Vertical component of the 60 N force ().. Horizontal component of the 60 N force ().3 State Newton's Second Law of Motion in words. () alculate the magnitude of the:.4 Normal force acting on the 5 kg block ().5 Tension in the string connecting the two blocks (7) [0]

8 Physical Sciences/P1 8 E/015 QUESTION 3 (Start on a new page.) hot air balloon is rising vertically at a constant velocity. When the hot air balloon reaches point a few metres above the ground, a man in the hot air balloon drops a ball which hits the ground and bounces. Ignore the effects of friction. GROUN The velocity-time graph below represents the motion of the ball from the instant it is dropped until after it bounces for the first time. The time interval between bounces is ignored. THE UPWR IRETION IS TKEN S POSITIVE. USE INFORMTION FROM THE GRPH TO NSWER THE QUESTIONS THT FOLLOW. v (m.s -1 ) 5,88 P,94 0 -,94 0,6,6 3, t (s) -19, Write down the magnitude of the velocity of the hot air balloon. (1) 3. alculate the height above the ground from which the ball was dropped. (3)

9 Physical Sciences/P1 9 E/015 alculate the: 3.3 Time at the point P indicated on the graph () 3.4 Maximum height the ball reaches after the first bounce (3) 3.5 istance between the ball and hot air balloon when the ball is at its maximum height after the first bounce (4) [13] QUESTION 4 (Start on a new page.) Two stationary steel balls, and, are suspended next to each other by massless, inelastic strings as shown in iagram 1 below. iagram 1 iagram 0, m all of mass 0, kg is displaced through a vertical distance of 0, m, as shown in iagram above. When ball is released, it collides elastically and head-on with ball. Ignore the effects of air friction. 4.1 What is meant by an elastic collision? () Immediately after the collision, ball moves horizontally backwards (to the left). all acquires kinetic energy of 0,1 J and moves horizontally forward (to the right). alculate the: 4. Kinetic energy of ball just before it collides with ball (Use energy principles only.) (3) 4.3 Speed of ball immediately after the collision (4) 4.4 Magnitude of the impulse on ball during the collision (5) [14]

10 Physical Sciences/P1 10 E/015 QUESTION 5 (Start on a new page.) The diagram below shows a heavy block of mass 100 kg sliding down a rough 5 o inclined plane. constant force F is applied on the block parallel to the inclined plane as shown in the diagram below, so that the block slides down at a constant velocity. F 100 kg 5 o The magnitude of the kinetic frictional force (f k ) between the block and the surface of the inclined plane is 66 N. 5.1 Friction is a non-conservative force. What is meant by the term nonconservative force? () 5. learner states that the net work done on the block is greater than zero Is the learner correct? nswer only YES or NO. (1) 5.. Explain the answer to QUESTION 5..1 using physics principles. () 5.3 alculate the magnitude of the force F. (4) If the block is released from rest without the force F being applied, it moves 3 m down the inclined plane. 5.4 alculate the speed of the block at the bottom of the inclined plane. (6) [15]

11 Physical Sciences/P1 11 E/015 QUESTION 6 (Start on a new page.) The graph below shows the relationship between the apparent frequency (f L ) of the sound heard by a STTIONRY listener and the velocity (v s ) of the source travelling TOWRS the listener. 950 Graph showing apparent frequency (f L ) versus velocity of sound source (v s ) fl (Hz) v s (m s -1 ) 6.1 State the oppler effect in words. () 6. Use the information in the graph to calculate the speed of sound in air. (5) 6.3 Sketch a graph of apparent frequency (f L ) versus velocity (v s ) of the sound source if the source was moving WY from the listener. It is not necessary to use numerical values for the graph. () [9]

12 Physical Sciences/P1 1 E/015 QUESTION 7 (Start on a new page.) Three point charges, Q 1, Q and Q 3, carrying charges of +6 µ, -3 µ and +5 µ respectively, are arranged in space as shown in the diagram below. The distance between Q 3 and Q 1 is 30 cm and that between Q 3 and Q is 10 cm. Q 3 = +5 µ 30 cm Q 1 = +6 µ 10 cm Q = -3 µ 7.1 State oulomb's law in words. () 7. alculate the net force acting on charge Q 3 due to the presence of Q 1 and Q. (7) [9]

13 Physical Sciences/P1 13 E/015 QUESTION 8 (Start on a new page.) Two identical neutral spheres, M and N, are placed on insulating stands. They are brought into contact and a charged rod is brought near sphere M. harged rod M N When the spheres are separated it is found that 5 x 10 6 electrons were transferred from sphere M to sphere N. 8.1 What is the net charge on sphere N after separation? (3) 8. Write down the net charge on sphere M after separation. () The charged spheres, M and N, are now arranged along a straight line, in space, such that the distance between their centres is 15 cm. point P lies 10 cm to the right of N as shown in the diagram below. M 15 cm N 10 cm P 8.3 efine the electric field at a point. () 8.4 alculate the net electric field at point P due to M and N. (6) [13]

14 Physical Sciences/P1 14 E/015 QUESTION 9 (Start on a new page.) cell of unknown internal resistance, r, has emf ( ε ) of 1,5 V. It is connected in a circuit to three resistors, a high-resistance voltmeter, a low-resistance ammeter and a switch S as shown below. V ε = 1,5 V r S 4 Ω P Ω 3 Ω When switch S is closed, the voltmeter reads 1,36 V. 9.1 Which terminal of the ammeter is represented by point P? Write down only POSITIVE or NEGTIVE. (1) 9. alculate the ammeter reading. (3) 9.3 etermine the internal resistance of the cell. (7) 9.4 n additional resistor X is connected parallel to the 3 Ω resistor in the circuit. Will the reading on the ammeter INRESE, ERESE or REMIN UNHNGE? Give a reason for the answer. (4) [15]

15 Physical Sciences/P1 15 E/015 QUESTION 10 (Start on a new page.) 10.1 The output potential difference of an generator is 100 V at 0 Hz. simplified diagram of the generator is shown below. The direction of the current in the coil is from a to b. c b d a In which direction is the coil rotating? Write only LOKWISE or NTILOKWISE. (1) Starting from the position shown in the diagram, sketch a graph of the output potential difference versus time when the coil completes TWO full cycles. On the graph, clearly indicate the maximum potential difference (100 V) and the time taken to complete the two cycles. (3) State ONE way in which this generator can be used to produce a lower output potential difference. (1) 10. n electrical device is rated 0 V, W. alculate the maximum current output for the device when it is connected to a 0 V alternating current source. (5) [10]

16 Physical Sciences/P1 16 E/015 QUESTION 11 (Start on a new page.) 11.1 In the diagram below, green and blue light are successively shone on a metal surface. In each case, electrons are ejected from the surface. green 500 nm blue 400 nm What property of light is illustrated by the photoelectric effect? (1) Without any calculation, give a reason why the maximum kinetic energy of an ejected electron, using blue light, is GRETER THN that obtained using green light, for the same metal surface. () 11. The wavelength associated with the cut-off (threshold) frequency of a certain metal is 330 nm. alculate: The work function of the metal (4) 11.. The maximum speed of an electron ejected from the surface of the metal when light of frequency 1, x Hz is shone on the metal (5) [1] TOTL: 150

17 Physical Sciences/P1 1 E/015 T FOR PHYSIL SIENES GRE 1 PPER 1 (PHYSIS) GEGEWENS VIR FISIESE WETENSKPPE GR 1 VRESTEL 1 (FISIK) TLE 1: PHYSIL ONSTNTS/TEL 1: FISIESE KONSTNTES NME/NM SYMOL/SIMOOL VLUE/WRE cceleration due to gravity Swaartekragversnelling g 9,8 m s - Universal gravitational constant Universele gravitasiekonstant G 6,67 x N m kg Speed of light in a vacuum Spoed van lig in 'n vakuum c 3,0 x 10 8 m s -1 Planck's constant Planck se konstante h 6,63 x J s oulomb's constant oulomb se konstante k 9,0 x N m harge on electron Lading op elektron e -1,6 x Electron mass Elektronmassa m e 9,11 x kg Mass of the Earth Massa van die arde M 5,98 x 10 4 kg Radius of the Earth Radius van die arde R E 6,38 x 10 6 m

18 Physical Sciences/P1 E/015 TLE : FORMULE/TEL : FORMULES MOTION/EWEGING vf v f 1 = vi + a t Δx Δy = v iδt + a t v i + v f v i + v f = v i + a x or/of v f = v i + a y Δx = Δt or/of Δy = Δt FORE/KRG F net = ma p = mv max fs = μsn FnetΔt = Δp Δp = m - f m i m1m m1m F =G or/of =G d r f k 1 = v iδt + a t or/of = μ N k w = mg M d M g = G r F g = G WORK, ENERGY N POWER/REI, ENERGIE EN RYWING W = FΔx cos θ U = mgh or/of E P = mgh W 1 1 net = K or/of Wnet = Ek K = mv or/of E k = mv K = K f K i or/of Ek = Ekf Eki W W nc = K + U or/of Wnc = Ek + Ep P = t P ave = Fv ave WVES, SOUN N LIGHT/GOLWE, KLNK EN LIG or/of v = f λ v ± v L L L = fs or/of L b v ± v s v ± v b f E = W + where/waar o E k (max) E = hf and/en W 0 = hf0 and/en E f 1 T = f v ± v = f E = hf or/of k(max) 1 = mv max E = h c λ

19 Physical Sciences/P1 3 E/015 ELETROSTTIS/ELEKTROSTTIK kq Q r kq r W V = q 1 F= E = F E = q Q n = or/of e n = Q q e ELETRI IRUITS/ELEKTRIESE STROOMNE V R = I Rs = R1 + R = R R R p 1 W = Vq W = VI t W = I R t W = V Δt R emf ( ε ) = I(R + r) emk ( ε ) = I(R + r) q = I t W P = Δt P = VI P = I R V P = R LTERNTING URRENT/WISSELSTROOM Imax I rms = / I I = wgk maks V V = max rms / V Vwgk = maks P P average = V rms Irms / Pgemiddeld = V wgk I wgk average I rms = R / P = R Vrms Paverage = / R P gemiddeld I wgk gemiddeld = V wgk R