Physical Sciences Grade 12 P1 Western Cape Mock 2014 QP

Downloaded from hlayiso.com Physical Sciences/P1 1 CWED September 2014 NSC CAPE WINELANDS EDUCATION DISTRICT PHYSICAL SCIENCES: PHYSICS (P1) SEPTEMBER 2014 MARKS 150 TIME 3 hours This question paper consists of 14 pages and 3 data sheets. Copyright reserved

Downloaded from hlayiso.com Physical Sciences/P1 2 CWED September 2014 NSC INSTRUCTIONS AND INFORMATION 1. Write your name in the appropriate space on the ANSWER BOOK. 2. This question paper consists of TEN questions. Answer ALL the questions in the ANSWER BOOK. 3. Start EACH question on a NEW page in the ANSWER BOOK. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Leave ONE line between two sub questions, for example between QUESTION 2.1 and QUESTION 2.2. 6. Write neatly and legibly. 7. You may use a non-programmable calculator. 8. You may use appropriate mathematical instruments. 9. YOU ARE ADVISED TO USE THE ATTACHED DATA SHEETS. 10. Show ALL formulae and substitutions in ALL calculations. 11. Round off your FINAL numerical answers to a minimum of TWO decimal places. 12 Give brief motivations, discussions, et cetera where required Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 3 CWED September 2014 NSC QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Write only the letter (A–D) next to the question number (1.1–1.10) in the ANSWER BOOK. 1.1 John, who is standing in a lift, observes a 20N mass piece suspended from a spring balance fixed to the roof of the lift. He sees that the reading on the spring balance is less than 20N for a short time interval. During this short time interval the lift is … A. not moving. B. accelerating upwards. C. accelerating downwards. D. moving with constant velocity. (2) 1.2 The gravitational force which the earth exerts on the moon is ….. A. directly proportional to the distance between their centres. B. inversely proportional to the mass of the moon. C. inversely proportional to the product of the mass of the moon and the mass of the earth. D. inversely proportional to the square of the distance between their centres. (2) 1.3 Two trolleys, X (mass m ) and Y (mass 2m) are stationary on a horizontal plane. There is a compressed spring between the two trolleys as shown in the diagram below. The spring is now released. How will the momentum of the trolleys compare? The momentum of trolley X …… A. Will be greater than the momentum of trolley Y. B. Will be less than the momentum of trolley Y. C. Will have the same magnitude as the momentum of trolley Y. D. Will be identical to the momentum of trolley Y. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 4 CWED September 2014 NSC 1.4 The graph below shows the position of a particle, with time, moving in a straight line in a vertical plane. Which ONE of the following velocity – time graphs best represents the motion of the particle? (2) 1.5 A ball is thrown vertically upwards. Which ONE of the following physical quantities of the ball will be zero when the ball reaches maximum height? A. Acceleration B. Kinetic energy C. Gravitational potential energy D. Weight (2) 1.6 A vehicle is travelling at a constant speed towards a stationary observer. Its hooter produces sound waves of frequency 400 Hz. Ignore the effects of wind. The sound heard by the observer will most likely have a frequency, in hertz, of … A. 400 B. 350 C. 380 D. 480 (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 5 CWED September 2014 NSC 1.7 The centres of two identical metallic spheres, each carrying a charge Q, are a distance r apart. Which ONE of the following pairs of changes (that are made simultaneously) will double the electrostatic force that one charged sphere exerts on the other? Distance between centres of Magnitude of charges spheres r A decrease distance to double the charge on each sphere 2 r Q B decrease distance to reduce the charge on one sphere to 2 2 r Q C decrease distance to reduce the charge on each sphere to 2 2 r D decrease distance to double the charge on each sphere 2 (2) 1.8 When electrical energy must be transported over long distances, the energy loss can be minimized if: A. the current is high and the voltage is low B. the voltage is high and the current is low C. both the current and voltage is low D. both the current and voltage is high (2) 1.9 Which ONE of the following graphs best represents the relationship between the electrical power and the current in a given ohmic conductor? A P B P I I C P D P I I (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 6 CWED September 2014 NSC 1.10. The two resistors in circuit 1 below are identical. They are connected in series to a cell of emf V and negligible internal resistance. The power dissipated by each resistor is P. The two resistors are now connected in parallel, as shown in circuit 2 below. The power dissipated by each resistor in the circuit 2 is … A 2P B 4P C 8P D 16P (2) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 7 CWED September 2014 NSC QUESTION 2 [START ON A NEW PAGE] 2.1 Truck A, of mass 4 500 kg travels at a CONSTANT VELOCITY OF 50 km·h-1 while towing Bakkie B, of mass 1 250 kg. The engine of Truck A produces a force of 11 270 N. The road surface exerts a friction force of 8 820 N on Truck A. 2.1.1 Write down Newton’s Second Law of motion in words. (2) 2.1.2 Draw a free-body diagram showing ALL the forces acting on Truck A. The length of the vectors should be an indication of their relative magnitudes.(6) 2.1.3 Calculate the coefficient of kinetic friction for tyre rubber on the road surface. (3) 2.1.4 Calculate the force of friction exerted by the road surface on Bakkie B. (3) 2.1.5 Calculate the tension in the tow rope. (3) 2.2 Truck A suddenly stops. Unfortunately Bakkie B has no brakes and slams into the rear of Truck A and Bakkie B comes to an immediate stop. As a result of the collision, the tow rope breaks Bakkie B Truck A 2.2.1 Write down the Law of Conservation of Momentum in words. (2) 2.2.2 Calculate the speed of Truck A immediately after the collision. (4) 2.2.3 Using Newton’s First Law of motion explain why it is always advisable to tow with a solid bar instead of a tow rope. (2) [25] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 8 CWED September 2014 NSC QUESTION 3 [BEGIN ON A NEW PAGE] Sandile, who is standing on a platform, throws a small metal ball vertically upward, from a height of 1,73 m above the ground, into the air at 8 m·s-1. The ball travels pass the top of the building and returns to Sandile’s hand which is still at 1,73 m above the ground. Ignore the effects of friction. Top floor window 2,5 m building 8 m·s-1 1,73 m ground platform 3.1 With what speed does the ball strike Sandile’s hand? (1) 3.2 Using an equation of motion and NOT energy principles, calculate the maximum height that the ball reaches above the ground. (4) 3.3 If a window on the top floor of the building is at a height of 2,5 m above Sandile’s hand, calculate the time taken for the ball, from the moment it was thrown, to pass the top of the window on its return to Sandile’s hand. (5) 3.4 Taking upward direction as positive, draw a sketch graph of position versus time graph of the ball’s motion from the moment it left Sandile’s hand until it lands back into his hands. Indicate all relevant position values. Use Sandile’s hand as reference. (5) [15] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 9 CWED September 2014 NSC QUESTION 4 [BEGIN ON A NEW PAGE] A rescue helicopter is stationary (hovers) above the ground. It lowers a crate containing medical supplies with a mass 50 kg onto the ground below. When the crate is at a height of 20 m above the ground it has a speed of 2 m·s-1. The crate is lowered at a constant acceleration onto the ground with a cable, where it eventually comes to rest. Assume there is no sideways motion during the descent. Air friction is NOT to be ignored. 4.1 Define a non-conservative force. (2) 4.2 Identify TWO non-conservative forces acting on the crate during its downward descent (motion). (2) 4.3 Draw a free-body diagram showing ALL the forces acting on the crate while it is being lowered to the ground. (3) 4.4 Write down the work-energy theorem in words. (2) 4.5 Using the work energy theorem, calculate the acceleration of the crate as it is lowered to the ground. (6) [15] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 10 CWED September 2014 NSC QUESTION 5 [BEGIN ON A NEW PAGE] Use the diagram below to answer the following questions. 5.1 Identify the medical device shown in the diagram. (1) 5.2 Explain very briefly how the device functions and what it may be used for. (2) 5.3 A fire truck with its siren on, moves away at constant velocity from a person standing next to the road. The person measures a frequency which is 90% of the frequency of the sound emitted by the siren of the fire truck. 5.3.1 Name the phenomenon observed. (1) 5.3.2 If the speed of sound in air is 340 m·s-1, calculate the speed of the fire truck. (4) [8] QUESTION 6 [BEGIN ON A NEW PAGE] Three +100 µC point charges, A, B and C, are equally spaced on a straight line in a vacuum. The charges are a distance of 3 cm from each other as shown in the sketch below. 6.1 Define in words electric field at a point. (2) 6.2 Draw the electric field lines associated with charge A only. (2) 6.3 Calculate the magnitude of the electric field strength at the position where charge B is and due to charge A only. (3) 6.4 Write down Coulomb’s Law in words. (2) 6.5 Calculate the net electrostatic force experienced by point charge C due to charges A and B. (8) [17] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 11 CWED September 2014 NSC QUESTION 7 [BEGIN ON A NEW PAGE] Candice and Andisiwe conduct an investigation to determine the emf (ε) and the internal resistance (r) of an unknown battery by experiment using three resistors. They use the circuit below with first one resistor in series, then two resistors in series and then three resistors in series. They also connect a voltmeter and an ammeter in this circuit. When switch S was closed, they obtained the following results: Number of resistors Voltmeter reading (V) Ammeter reading (A) 3 10,2 1,5 2 9,6 2,0 1 7,8 3,5 7.1 Sketch this circuit in your answer book. Show in your sketch where the learners connected the ammeter and the voltmeter. (2) 7.2 Calculate the value of ε and r that they obtained in their investigation by using their results. (7) [9] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 12 CWED September 2014 NSC QUESTION 8 [BEGIN ON A NEW PAGE] In the circuit represented below, the battery has an unknown internal resistance and an emf of 12 V. When current flows through the circuit, the voltmeter across the battery reads 10 V and a voltmeter across R2 reads 4 V 8.1 Explain what is meant by the emf of a cell. (1) 8.2 Calculate the current through R1. (4) 8.3 Determine the internal resistance of the battery. (3) 8.4 Determine the resistance of R3. (4) 8.5 Explain what would happen to the current and resistance in the circuit if R3 was removed from the circuit and replaced with a wire of negligible resistance. Hence what will happen to the reading on V1. (4) [16] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 13 CWED September 2014 NSC QUESTION 9 [BEGIN ON A NEW PAGE] Electric motors are used in pumps, fans and compressors. Electric motors can be either AC or DC. The diagram below illustrates one of these types of electric motors. 9.1 What type of electric motor (AC or DC) is illustrated in the diagram? Give a reason for your answer. (2) 9.2 The diagrams A to D below show four positions in sequence during the anti-clockwise rotation of the coil of a simple AC generator. 9.2.1 Name the fundamental principle on which generators work. (1) 9.2.2 What is the purpose of the slip rings in an AC generator? (1) 9.2.3 By referring to the relative positions of the coil in positions A to D, draw the corresponding graph of potential difference versus time for one full rotation (A to D to A). Indicate the positions of the coil (by using the letters A to D) on your graph. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 14 CWED September 2014 NSC 9.3 A certain AC generator (alternator) produces a peak current (Imax) of 6,43 A when connected to an electrical heater of resistance 48,4 Ω. 9.3.1 Calculate the rms current (Irms) produced by the generator. (3) 9.3.2 Calculate the peak voltage (Vmax) output of the generator. (5) [15] QUESTION 10 [BEGIN ON A NEW PAGE] The apparatus below was used to explore the photo-electric effect using a piece of zinc metal and light of a particular frequency. Use the diagram below to answer the following questions. C 10.1 Provide labels for B and C. (2) 10.2 Define the term” photo-electric effect” (2) 10.3 The learners observe that when component B is irradiated with light of wavelength of 100 nm, a current is detected in the ammeter. The work function of the metal B is 8,7 x 10-19 J. Calculate the speed at which the electrons are emitted. (6) [10] GRAND TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 15 CWED September 2014 NSC 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 NAME/NAAM SYMBOL/SIMBOOL VALUE/WAARDE Acceleration due to gravity g 9,8 m·s-2 Swaartekragversnelling Gravitational constant G 6,67 x 10-11 N⋅m2⋅kg-2 Swaartekragkonstante Radius of Earth RE 6,38 x 106 m Straal van Aarde Coulomb’s constant K 9,0 x 109 N⋅m2·C-2 Coulomb se konstante Speed of light in a vacuum c 3,0 x 108 m·s-1 Spoed van lig in 'n vakuum Charge on electron e -1,6 x 10-19 C Lading op elektron Electron mass me 9,11 x 10-31 kg Elektronmassa TABLE 2: FORMULAE/TABEL 2: FORMULES MOTION/BEWEGING v f = v i + a ∆t ∆x = v i ∆t + 21 a∆t 2 or/of ∆y = v i ∆t + 21 a∆t 2  v +vf   v + vf  2 2 2 2 v f = v i + 2a∆x or/of v f = v i + 2a∆y ∆x =  i  ∆t or/of ∆y =  i  ∆t  2   2  FORCE / KRAG Fnet = ma p = mv Fnet ∆t = m∆v w = mg ∆p = mv f − mv i Gm1m 2 GM F= g= r2 r2 f fs µk = k µs = (maks ) N N Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 16 CWED September 2014 NSC WORK ENERGY AND POWER / ARBEID, ENERGIE EN DRYWING W = F∆x cos θ U = mgh or/of Ep = mgh 1 1 Wnet = ∆K or/of Wnet = ∆Ek K= mv 2 or/of Ek = mv 2 2 2 ∆K = K f − K i or/of ∆Ek = Ekf − Eki W Wnc = ∆K + ∆U or/of Wnc = ∆E k + ∆E p P= ∆t Pave = Fv ave WAVES, SOUND AND LIGHT/GOLWE, KLANK EN LIG 1 v = fλ T= f v ± vL hf fL = fs E = hf or/of E = v ± vs λ E = Wo + K max or/of E = Wo + Ek (max) where/waar 1 2 1 2 E = hf and/en W0 = hf 0 and/en K max = mv max or/of Ek (max) = mv max 2 2 ELECTROSTATICS / ELEKTROSTATIKA kQ 1Q 2 kQ F= 2 (k = 9,0 x 109 N⋅m2·C-2) E= (k = 9,0 x 109 N⋅m2·C-2) r r2 F W E= V= q q Q Q n= of/or n = e qe CURRENT ELECTRICITY / STROOMELEKTRISITEIT V R= emk ( ε ) = I(R + r ) I R = r1 + r2 + r3 + ... 1 1 1 1 q = I∆t = + + + ... R r1 r2 r3 W = Vq W P= ∆t W = VI ∆ t P = VI W= I2R ∆ t 2 P = I2R V ∆t W= V2 R P= R Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P1 17 CWED September 2014 NSC ALTERNATING CURRENT / WISSELSTROOM/ I Pave = VrmsIrms Irms = max 2 2 Pave = IrmsR V 2 Vrms Vrms = max Pave = 2 R Copyright reserved Please turn over