Physical Sciences Grade 12 Paper 1 KZN Prelim 2024 Memo

Downloaded from hlayiso.com FINAL NATIONAL SENIOR CERTIFICATE GRADE 12 PHYSICAL SCIENCES P1 (PHYSICS) PREPARATORY EXAMINATION SEPTEMBER 2024 MARKING GUIDELINES MARKS: 150 These Marking Guidelines consist of 12 pages. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 2 September 2024 Preparatory Examination NSC – Marking Guideline QUESTION 1: MULTIPLE-CHOICE QUESTIONS 1.1 B 1.2 B 1.3 D 1.4 D 1.5 A 1.6 C 1.7 B 1.8 C 1.9 A 1.10 C [20] QUESTION 2 2.1 2.1.1 When a resultant/net force acts on an object, the object will accelerate in the direction of the force. The acceleration is directly proportional to the force  and inversely proportional to the mass of the object.  (2) 2.1.2 Accepted labels W Fg/Fw/Weight/Gravitational force fk f/friction/Kinetic friction N FN/Normal force F FApplied force / 40N T FT/ Tension (5) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 3 September 2024 Preparatory Examination NSC – Marking Guideline 2.1.3 MARKING CRITERIA  Mark for formula Fnet = ma.   Mark for substitution of acceleration of 0,5 in Fnet = ma.   Mark for calculation of the kinetic friction.   Left hand side substitution. , one for each block.  Mark for the answer. UP THE INCLINE AS POSITIVE: For 3 kg block: Fnet = ma T + FgII + (−fk ) + (−F) = ma [T + (3)(9.8) sin 3 00 − (0,2)[(3)(9.8) cos 3 00 ] − 40 ]= 3(0.5)  T = 31,89N For block X: Fnet = ma F + (−T) = ma X((9.8) − 31.89)= X(0.5) X = 3.43kg (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 4 September 2024 Preparatory Examination NSC – Marking Guideline 2.2 2.2.1 Each body in the universe attracts every other body with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres. (2) 2.2.2 Gm1 m2 F=  r2 (𝟔.𝟔𝟕×𝟏𝟎−𝟏𝟏 )(𝟓.𝟗𝟖×𝟏𝟎𝟐𝟒 )(𝟕.𝟑𝟓×𝟏𝟎𝟐𝟐 ) 1.91 × 1020    (𝟔.𝟑𝟖×𝟏𝟎𝟔 +𝟏.𝟐×𝟏𝟎𝟖 +𝐑 𝐦 )𝟐  R m = 2.65 × 108 m  (5) [20] QUESTION 3 3.1 3.1.1 An object which has been given an initial velocity and then it moves under the influence of the gravitational force only. NB: Object will only receive a mark if used in the correct contexts of vertical motion. (2) 3.1.2 (1) 3.1.3 Zero/ 0 (J) (1) 3.2.1 Upwards Positive Upwards Negative 𝑣𝑓 = 𝑣𝑖 + 𝑎𝛥𝑡  𝑣𝑓 = 𝑣𝑖 + 𝑎𝛥𝑡  0 = 10 + (−9,8)𝛥𝑡  0 = −10 + (9,8)𝛥𝑡  𝛥𝑡 = 1,02𝑠  𝛥𝑡 = 1,02𝑠  (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 5 September 2024 Preparatory Examination NSC – Marking Guideline 3.2.2 DOWNWARD POSITIVE: BALL A: 1 Δy = vi Δt + 2 aΔt 2 1 yA = (−10)t + 2 (9.8)t 2  yA = −10t + 4.9t 2 BALL B: 1 yB = (0)(t − 0.5) + 2 (9.8)(t − 0.5)2 8 + yA = yB 8+= −10𝑡 + 4.9𝑡 2 = 4,9(t − 0.5)2 −10t + 4.9t 2 = 4.9t 2 − 4,9t + 1,225 − 8 ∴ t = 1.33s  DOWNWARD NEGATIVE: BALL A: 1  Δy = vi Δt + aΔt 2 2 1 yA = (10)t + 2 (−9.8)t 2  yA = 10t − 4.9t 2 BALL B: 1 yB = (0)(t − 0.5) + (−9.8)(t − 0.5)2  2 8 + yB = yA 8 − 4.9t 2 + 4,9t − 1,225 = 10t − 4.9t 2 ∴ t = 1.33s  (4) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 6 September 2024 Preparatory Examination NSC – Marking Guideline 3.3.2 POSITIVE MARKING FROM 3.3. 8 Position (m) 0 0,5 1,02 1,33 t (s) Starting times (0.5 s; 8 m) for Ball B, (0s ; 0 m) for Ball A  1.33s the time at which balls meet  (3) Correct shapes for the graphs  [14] QUESTION 4 4.1 The total linear momentum of an isolated system remains constant (is conserved) NB: If closed system is used award 1 mark. (2) 4.2 1 𝐸𝐾 = 2 𝑚𝑣 2  1 258750 = 2 (2300)𝑣 2  𝑣 = 15m.s-1 (3) 4.3 ∑ pbefore = ∑ pafter  m1 vi1 + m2 vi2 = (m1 + m2 )vf mT (20) + (2300 − mT )(−10) = (2300)(15)  mT = 1916,67kg (4) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 7 September 2024 Preparatory Examination NSC – Marking Guideline 4.4 POSITIVE MARKING FROM 4.3 Δp = m(vf − vi )  Δp = 1916.67(15 − 20)  Δp = −9583.35 kg.m.s-1 ∴Impulse = 9583.35 N.s (3) [12] QUESTION 5 5.1 No. Presence of kinetic frictional force/rough surface (2) 5.2 The work done on an object by a net force is equal to the change in the object's kinetic energy. (2) 5. 3 𝑊𝑛𝑒𝑡 = 𝛥𝐸𝑘  1 𝑚𝑔𝛥𝑦𝑐𝑜𝑠𝜃 + 𝑊𝑓𝑘 = 𝑚(𝑣𝑓 2 − 𝑣𝑖 2 ) 2 1 (2)(9.8)(2)𝑐𝑜𝑠00 +𝑊𝑓𝑘 = 2 (2)(52 − 02 )  𝑊𝑓𝑘 = −14.20 J Option 2: 𝑊𝑛𝑐 = 𝛥𝐸𝑘 + 𝛥𝐸𝑝  1 𝑊𝑓𝑘 = 𝑚(𝑣𝑓 2 − 𝑣𝑖 2 ) + 𝑚𝑔(ℎ𝑓 − ℎ𝑖 ) 2 1 𝑊𝑓𝑘 = 2 (2)(52 − 02 ) +(2)(9.8)(0 − 2)  𝑊𝑓𝑘 = −14.20 J (6) [10] QUESTION 6 6.1 Doppler effect is the change in frequency (or pitch) of the sound detected by a listener, because the sound source and the listener have different velocities relative to the medium of sound propagation. (2) 6.2 𝑣 = 𝑓×𝜆  340 = 𝑓(0.24)  𝑓 = 1416.67 Hz (3) 6.3 POSITIVE MARKING FROM 6.2 𝐯±𝐯 𝐟𝐋 = 𝐯±𝐯𝐋 𝐟𝐬  𝐬   340+0 1466.67 = 340−v (1416.67)  s ∴ vs = 11.59 m.s-1 (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 8 September 2024 Preparatory Examination NSC – Marking Guideline Δx v= Δt x 11.59 = 15 x = 173.85m 6.4 Doppler flowmeter.  Or Determine heartbeat of foetus. (1) [12] QUESTION 7 7.1 7.1.1 The magnitude of the electrostatic force exerted by one point charge on another point charge is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. (2) 7.1.2 T  FE  (3) Fg  7.1.3 Fnet = ma kQ1 Q2  mg + (−T) + (− ) = ma r2 (9×109 )(50×10−9 )(20×10−9 ) [m(9.8) − 8 − ]  = 0 (4×10−2 )2 m = 0.82 kg  ms = 0.82 × 2 = 1.63kg (6) 7.2 7.2.1 The electric field at a point is the electrostatic force experienced per unit positive charge placed at that point. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 9 September 2024 Preparatory Examination NSC – Marking Guideline 7.2.2 B: The field from both charges are in the same direction. 1 C:𝐸𝛼 𝑟 2 , C is closer to q2 than q1, and q2 > q1 Or kq 2 𝑘𝑞1 −2 2 > (5𝑋10 ) (65𝑋10−2 )2 (2) 7.2.3 Enet = E1 + (−E2 ) kQ kQ Enet = r22 +(− r21 ) (9×109 )(30×10−6 ) (9×109 )(90×10−6 ) Enet = −  (20×10−2 )2 (80×10−2 )2 ∴ Enet = 5484375N.C-1 to the left (6) [21] QUESTION 8. 8.1 The potential difference across a conductor is directly proportional to the current in the conductor at constant temperature. (2) 8.2 8.2.1 1 1 1 = + 𝑅𝑝 𝑅1 𝑅2 1 1 1 = +  𝑅𝑝 18 6 𝑅𝑝 = 4,5 𝛺 𝑉  𝑅= 𝐼 𝑉 4,5 =  0,4 𝑉 = 1,8𝑉 (4) 8.2.2 POSITIVE MARKING FROM 8.2.1 V2 Δt W=  R  (1,8)2 (300) W=( ) (18) W = 54 J OR (4) V R= I Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 10 September 2024 Preparatory Examination NSC – Marking Guideline 1,8 18 = I I = 0,1A OR W = VI△t W = I2R△t   W = [(1,8 X0,1 ) x 300] W = [(0,1)2 (18) (300) ]   W = 54J W = 54J  8.2.3 POSITIVE MARKING FROM 8.2.1 AND 8.2.2 𝑉𝑖𝑛𝑡𝑒𝑟𝑛𝑎𝑙 = 𝐼𝑟    5-1,8 = 0,4r r=8Ω If learners end here award full marks r = 4 Ω OR ε = I(R + r)   5 = (0,4)(4,5 + r)  r=8Ω r = 4 Ω (4) 8.3 Increases. (1) [15] QUESTION 9 9.1 9.1.1 DC (1) 9.1.2 Mechanical (energy) is converted to Electrical (energy). (1) 9.1.3 Y.  (1) 9.1.4 Maximum.  (1) 9.2 9.2.1 𝐼 𝐼𝑟𝑚𝑠 = 𝑚𝑎𝑥  √2 (5) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 11 September 2024 Preparatory Examination NSC – Marking Guideline 6 𝐼𝑟𝑚𝑠 =  OR √2 Vmax = Vrms√2 Vmax = 210√2 𝐼𝑟𝑚𝑠 = 4.24A Vmax = 296,98V 𝑉𝑟𝑚𝑠 = 𝐼𝑟𝑚𝑠 𝑅  V 𝑅 = I max  210 = 4.24𝑅 max 296,98 𝑅 = 49.53𝛺 R= 6  R = 49, 50 Ω 9.2.2 POSITIVE MARKING FROM 9.2.1 2 V2rms Pave = Vrms . I  Pave = Irms .R  Pave =  R Pave = (210)(4.24)  2 Pave = (4,24) (49,53)  (210)2 Pave = 890.43W Pave = (49.53) Pave = 890.40W Pave = 890,37W W P = Δt W 890.40 = 7200 W = 6,41 X 106 J (5) [14] QUESTION 10 10.1 The process whereby electrons are ejected from a metal surface when light of suitable frequency is incident on that surface. (2) 10.2 At Ek(max) = 0 J: 1 f0 = c(λ)  f0 = (3 × 108 )(3.6 × 106 )  f0 = 1.08 × 1015 Hz  (3) 10.3 hc = hf0 + Ek(max)  λ (6,63×10−34 )(3,0×108 ) ( = (6,63X10-34) (1,08X1015)  + Ek(max) 5,6×106  Ek(max) = 3,98X10-19J  (5) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P1 12 September 2024 Preparatory Examination NSC – Marking Guideline 10.4 10.4.1 REMAIN THE SAME (1) 10.4.2 INCREASES (1) [12] TOTAL: 150 Copyright reserved Please turn over