PHYSICAL SCIENCES: PHYSICS (PAPER 1)
GRADE 12
NOVEMBER 2019
MEMORANDUM
NATIONAL SENIOR CERTIFICATE

QUESTION 1
1.1 C ✓✓ (2)
1.2 A ✓✓ (2)
1.3 A✓✓ (2)
1.4 D ✓✓ (2)
1.5 B ✓✓ (2)
1.6 D ✓✓ (2)
1.7 A ✓✓ (2)
1.8 B ✓✓ (2)
1.9 D ✓✓(2)
1.10 C ✓✓ (2)
[20]

QUESTION 2
NOTE: -1 mark for each key word/phrase omitted in the correct context (2)
2.1 When a resultant/net force acts on an object, the object will accelerate in the direction of the force with an acceleration that is directly proportional to the force and inversely proportional to the mass of the object. ✓✓
OR
The resultant/net force acting on an object is equal to the rate of change of momentum of the object (in the direction of the resultant/net force.) ✓✓ (2)
2.2 
18

  Accept the following symbols 
N FN/Normal/Normal force 
Ff / fk / fr / frictional force/kinetic frictional force
Fg,/mg/weight/FEarth on block/19,6 N/gravitational force 
Tension/FT / FA / F / Fs 

Notes

  • Mark is awarded for label and arrow. 
  • Do not penalise for length of arrows.
  • Deduct 1 mark for any additional force. 
  • If force(s) do not make contact with body/dot: Max: 43
  • If arrows missing/Indien pyltjies uitgelaat is: Max./Maks: 43 (4)

2.3

For the 2 kg (P) block:
Fnet = ma
T + (- wll) + (- fk) = ma
T – (wll + fk) = ma
T – (2)(9,8)sin30°✓ – 2,5✓= 2a ✓
T – 9,8 – 2,5 = 2a
T – 12,3 = 2a ……….(1)
For the 3 kg (Q) block:
Fx + (-T) + (- wll) = ma
Fx – (T + wll) = ma
[40 cos 25°✓ – T – (3)(9,8)sin30°✓] ✓ = 3a
36,25 – T – 14,7 = 3a
21,55 – T = 3a ………….(2)
9,25 = 5 a
a = 1,85 m∙s-2✓

Marking criteria

  • Formula ✓
  • Substitution of for 2 kg: (2)(9,8)sin30°✓
  • Substitution of -2,5 N
  • 2a OR 3a ✓
  • Calculate Fx: 40 cos 25° ✓ (40 Sin 65°)
  • Substitution of/for 3 kg: (3)(9,8)sin30°✓
  • Left hand side substitution for 3 kg
  • Final answer: 1,85 m∙s-2✓
Systems Approach (Massless String Approximation
(Max 5/8 marks)
Fnet = ma
Fx + (- wll) + (- fk) = ma
Fx – (wll + fk) = ma
40cos25° ✓ – (5)(9,8)sin30°✓ – 2,5✓= 5a
a = 1,85 m∙s-2 ✓

(8)
2.4 Greater than 
Fnet increases. 

ACCEPT
There is no friction.
OR
The surface is smooth (2)
[16]

QUESTION 3
3.1 (Motion during which) the only force acting is the force of gravity. ✓✓ (2 or 0) (2)
3.2 Marking criteria:

  • Any appropriate formula for Δy
  • Whole substitution to calculate 5,1 m
  • 40 + answer from calculation
  • Final answer: 45,10 m ✓(Accept/aanvaar 45,1 m)

OPTION 1
UPWARDS AS POSITIVE:
vf2 = vi2 + 2aΔy ✓
0 = (10)2 + (2)(- 9,8)Δy ✓
Δy = 5,10 m (5,102 m)
Height = 40 + 5,10 ✓
= 45,10 m ✓

DOWNWARDS AS POSITIVE:
vf2 = vi2 + 2aΔy✓
0 = (-10)2 + (2)( 9,8)Δy ✓
Δy = - 5,10 m (5,102)
Height = 40 + 5,10 ✓
= 45,10 m ✓

OPTION 2
UPWARDS AS POSITIVE:
vf = vi + aΔt
0 = (10) + (- 9,8)Δt
Δt = 1,02 s
Δy = viΔt + ½ aΔt2✓
= (10)(1,02) + ½ (-9,8)(1,02)2✓
= 5,10 m

OR
Δy=(v1  + vf)Δt
           2
=(10 + 0)(1,02)
       2
= 5.10m
Height = 40 + 5,10 ✓
= 45,10 m ✓

DOWNWARDS AS POSITIVE:
vf = vi + aΔt
0 = (-10) + ( 9,8)Δt
Δt = 1,02 s
Δy = viΔt + ½ aΔt2
= (-10)(1,02) + ½ (9,8)(1,02)2
= 5,10 m
Height = 40 + 5,10 ✓
= 45,10 m ✓
Accept swopping of vi and vf

OPTION 3
UPWARDS AS POSITIVE:
Δy = viΔt + ½ aΔt2
0 = (10) Δt + ½(-9,8)Δt2
Δt = 2,04 s
Δy = viΔt + ½ aΔt2✓
= (10)(1,02) +½ (-9,8)(1,02)2✓
= 5,10 m
Height = 40 + ✓5,10
= 45,10 m ✓

DOWNWARDS AS POSITIVE:
Δy = viΔt + ½ aΔt2
0 = (-10) Δt + ½(9,8)Δt2
Δt = 2,04 s
Δy = viΔt + ½ aΔt2✓
= (-10)(1,02) + ½ (9,8)(1,02)2✓
= - 5,10 m
Height = 40 + 5,10 ✓
= 45,10 m ✓

OPTION 4
UPWARDS AS POSITIVE:
Δy = viΔt + ½ aΔt2
0 = (10)Δt + ½(-9,8)Δt2
Δt = 2,04s
Δy=(v1  + vf)Δt
           2
=(10 + 0)(1,02)
       2
= 5.10m
Height = 40 + 5,10 ✓
= 45,10 m ✓

DOWNWARDS AS POSITIVE:
Δy = viΔt + ½ aΔt2
0 = (-10) Δt + ½(9,8)Δt2
Δt = 2,04 s
Δy=(v1  + vf)Δt
           2
=(10 + 0)(1,02)
       2
= 5.10m
Height = 40 + 5,10 ✓
= 45,10 m ✓
Accept swopping of vi and vf

OPTION 5
E(mech)roof = E(mech)top
(Ep + Ek)roof = (Ep + Ek)top
(mgh + ½ mv2)roof/dak = (mgh + ½ mv2)top
[m(9,8)(0) + ½m (10)2 = m(9,8) (h)+ 0)] ✓
h = 5,10 m
Height = 40 + 5,10 ✓
= 45,10 m✓

OPTION 6
Wnet = ΔEk ✓
wΔxcosθ = ½ mvf2 – ½ mvi2
(m)(9,8)Δxcos180º= 0 – ½ m(10)2✓
Δx = 5,10 m
Height = 40 + 5,10 ✓
= 45,10 m ✓

OPTION 7
Wnc = ΔEp + ΔEk✓
0 = m(9,8)(hf – 0) + ½ m( 0 – 102) ✓
hf = 5,10 m
Height = 40 + 5,10✓
= 45,10 m✓

OPTION 8
Marking criteria:

  • Appropriate formula
  • Substitution left
  • Substitution right
  • Final answer: 45,10 m✓
    Any one

E(mech)roof = E(mech)top
(Ep + Ek)roof = (Ep + Ek)top
(mgh + ½ mv2)roof/dak = (mgh + ½ mv2)top
[m(9,8)(0) + ½m (10)2 = m(9,8) (h)+ 0)] ✓
h = 45,10 m (4)
3.3 9,8 m·s-2 ✓downwards✓ (2)
3.4 Marking criteria

  • Calculation/use of 10,26 m.
  • Appropriate formula to calculate Δt
  • Substitution for stone A ✓
  • Substitution for stone B ✓
  • Calculating time difference between two stones. ✓
  • Final answer: 1,34 (s) ✓

OPTION 1
UPWARDS AS POSITIVE:
Displacement from roof to meeting point = -40 + 29,74 = - 10,26 m
Stone A
ΔyA = viΔt + ½aΔt2
-10,26 ✓= 10Δt + ½(-9,8)Δt2
Δt = 2,79 s
vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s) ✓

Stone B
ΔyB = viΔt + ½aΔt2
-10,26 = 0 + ½(-9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45✓= 1,34 (s) ✓
OR
[-10,26 = 0(2,79 – x) + ½ (-9,8)(2,79 – x)2✓]✓
x = 1,34 (s)✓

DOWNWARDS AS POSITIVE:
Displacement from roof to meeting point= 40 - 29,74 = 10,26 m
Stone A
ΔyA = viΔt + ½aΔt2
10,26 = -10Δt + ½(9,8)Δt2
Δt = 2,79 s
vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s)✓

Stone B
ΔyB = viΔt + ½aΔt2
10,26 = 0 + ½(9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 ✓ = 1,34 (s) ✓
OR
[-10,26 = 0(2,79 – x) + ½ (-9,8)(2,79 – x)2✓]✓
x = 1,34 (s) ✓

OPTION 2
UPWARDS AS POSITIVE:
Displacement from roof to meeting point = - 40 + 29,74 = - 10,26 m
Displacement of stone A from max height to meeting point = -15,36 m

Stone A
vf = vi + aΔt
0 = 10 +(-9,8)Δt
Δt = 1,02 s
ΔyA = viΔt + ½aΔt2
-15,36 = 0 + ½(-9,8)Δt2
Δt = 1,77 s
Δttot = 1,77 + 1,02 = 2,79s

Stone B
ΔyB = viΔt + ½aΔt2
-10,26 ✓= 0 + ½(-9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 ✓ = 1,34 (s) ✓

vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s) ✓

DOWNWARDS AS POSITIVE:
Displacement from roof to meeting point = 40 - 29,74 = 10,26 m ✓
Displacement of ball A from max height to meeting point = 15,36 m

Stone A
vf = vi + aΔt
0 = -10 + (9,8)Δt
Δt = 1,02 s
ΔyA = viΔt + ½aΔt2
15,36 = 0 + ½(9,8)Δt2
Δt = 1,77 s
Δttot = 1,77 + 1,02 = 2,79s

Stone B
ΔyB = viΔt + ½aΔt2
10,26 = 0 + ½(9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 ✓ = 1,34 (s) ✓

vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s) ✓

OPTION 3
UPWARDS AS POSITIVE:
Displacement of stones A and B from roof to meeting point = - 40 + 29,74 = - 10,26 m

Stone A
vf = vi + aΔt
0 = 10 + (-9,8)Δt
Δt = 1,02 s
ΔyA = viΔt + ½aΔt2✓
- 10,26 = -10 + ½(-9,8) Δt2
Δt = 0,75 s
Δttot = 1,02 + 1,02 + 0,75 = 2,79 s

Stone B
ΔyB = viΔt + ½aΔt2
-10,26 = 0 + ½(-9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 = 1,34 (s) ✓

vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s)✓

DOWNWARDS AS POSITIVE:
Displacement of stones A and B from roof to meeting point = 40 - 29,74 = 10,26 m

Stone A
vf = vi + aΔt
0 = -10 + (9,8)Δt
Δt = 1,02 s
ΔyA = viΔt + ½aΔt2
10,26 ✓= 10 + ½ (9,8)Δt2
Δt = 0,75s
Δttot = 1,02 + 1,02 + 0,75 = 2,79 s

Stone B
ΔyB = viΔt + ½aΔt2
10,26 = 0 + ½(9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 ✓= 1,34 (s) ✓

vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45✓
= 1,34 (s)✓

OPTION 4
UPWARDS AS POSITIVE:
Displacement from roof to meeting point = - 40 + 29,74 = - 10,26 m

Stone A
ΔyA = viΔt + ½aΔt2
- 5,10 = 0 + ½(-9,8)Δt2
Δt = 1,02 s
ΔyA = viΔt + ½aΔt2 ✓
- 10,26 = -10 + ½(-9,8)Δt2
Δt = 0,75s
Δttot = 1,02 + 1,02 + 0,75 = 2,79 s

Stone B
ΔyB = viΔt + ½aΔt2
-10,26 = 0 + ½(-9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 ✓= 1,34 (s) ✓

vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s)✓

DOWNWARDS AS POSITIVE:
Displacement from roof to meeting point = 40 - 29,74 = 10,26 m

Stone A
ΔyA = viΔt + ½aΔt2
5,10 = 0 + ½(9,8)Δt2
Δt = 1,02 s
ΔyA = viΔt + ½aΔt2
10,26 = 10 + ½(9,8)Δt2
Δt = 0,75s
Δttot = 1,02 + 1,02 + 0,75 = 2,79 s

Stone B
ΔyB = viΔt + ½aΔt2
10,26 = 0 + ½(9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 = 1,34 (s)✓

vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s) ✓

OPTION 5
UPWARDS AS POSITIVE:
Displacement from roof to meeting point = - 40 + 29,74 = - 10,26 m
Displacement of stone A from max height to meeting point = -15,36 m

Stone A
vf2 = vi2 + 2aΔy
vf2 = (0)2 + (2)(- 9,8)(-15,36)
vf = - 17,35 m·s-1
vf = vi + aΔt
-17,35 = 0 + (-9,8)Δt ✓
Δt = 1,77 s
Δttot = 1,02 + 1,77 = 2,79 (s)

Related Items

Stone B
ΔyB = viΔt + ½aΔt2
-10,26 = 0 + ½(-9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45  = 1,34 (s) ✓

vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s)✓

DOWNWARDS AS POSITIVE:
Displacement from roof to meeting point = 40 - 29,74 = 10,26 m
Displacement of stone A from max height to meeting point = 15,36 m

Stone A
vf2 = vi2 + 2aΔy
vf2 = (0)2 + (2)(9,8)(15,36)
vf = - 17,35 m·s-1
vf = vi + aΔt
17,35 = 0 + (9,8)Δt ✓
Δt = 1,77 s
Δttot = 1,02 + 1,77 = 2,79 (s)

Stone B
ΔyB = viΔt + ½aΔt2
10,26 = 0 + ½(9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 ✓ = 1,34 (s) ✓

vf2 = vi2 + 2aΔy
= 02 + 2(9,8)(10,26)
vf = 14,18 m·s-1
vf = vi + aΔt
14,18 = 0 + (9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s) ✓

OPTION 6
UPWARDS AS POSITIVE:
Displacement from roof to meeting point/Verplasing vanaf dak tot by ontmoetingspunt = - 40 + 29,74 = - 10,26 m
Stone/Klip A
vf2 = vi2 + 2aΔy
vf2 = (-10)2 + (2)(- 9,8)(-10,26)
vf = - 17,35 m·s-1
vf = vi + aΔt
-17,35 = -10 + (-9,8)Δt ✓
Δt = 0,75 s
Ball A: Δt = 1,02 + 1,02 + 0,75 = 2,79 (s)

Stone B
ΔyB = viΔt + ½ aΔt2
-10,26 ✓= 0 + ½ (-9,8)Δt2
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 = 1,34 (s)✓
vf2 = vi2 + 2aΔy
= 02 + 2(-9,8)(-10,26)
vf = -14,18 m·s-1
vf = vi + aΔt
-14,18 = 0 + (-9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s) ✓

DOWNWARDS AS POSITIVE:
Displacement from roof to meeting point = 40 - 29,74 = 10,26 m
Stone/Klip A
vf2 = vi2 + 2aΔy
vf2 = [(10)2 + (2)(9,8)(10,26)
vf = 17,35 m·s-1
vf = vi + aΔt
17,35 = 10 + (9,8)Δt ✓
Δt = 0,75 s
Ball A: Δt = 1,02 + 1,02 + 0,75 = 2,79 (s) (6)

Stone B
ΔyB = viΔt + ½aΔt2
10,26 = 0 + ½(9,8)Δt2✓
Δt = 1,45 s (1,447 s)
x = 2,79 – 1,45 ✓ = 1,34 (s) ✓
vf2 = vi2 + 2aΔy
= 02 + 2(9,8)(10,26)
vf = 14,18 m·s-1
vf = vi + aΔt
14,18 = 0 + (9,8)Δt✓
Δt = 1,45 s
x = 2,79 – 1,45 ✓
= 1,34 (s) ✓
3.5.2 a ✓ (1)
3.5.3 f ✓ (1)
3.5.4 c ✓ (1)
[18]
3.5.1 d ✓ Accept / Aanvaar ( 0 – e; 0 – d; d – e) (1)

QUESTION 4
4.1 NOTE: -1 mark for each key word/phrase omitted in the correct context.
Isolated system is a system on which the resultant/net external force is zero.✓✓
OR
Isolated system is one that has no net / external force acting on it.(2)
4.2.1 p = mv ✓
24 = m (480) ✓
m = 0,05 kg ✓ (3)
4.2.2 Marking criteria

  • Appropriate formula including Fnet or Wnet.
  • Substitutions ✓✓
  • Final answer: 2 000 N ✓
  • Correct direction: west or left ✓

POSITIVE MARKING FROM QUESTION 4.2.1
OPTION 1
FnetΔt = Δp
FnetΔt = (pbullet)f - (pbullet)i
FnetΔt = (mvbullet)f - (mvbullet)i
Fnet(0,01) ✓ = (0,05)(80) – 24 ✓ or/of (0,05)(80) – (0,05)(480)
Fnet = -2 000 N
Fnet= 2 000 N ✓ west ✓

OPTION 2
vf = vi + aΔt
80 = 480 + a(0,01) ✓
a = - 40 000 m∙s-2
Fnet= ma ✓
= (0,05)(-40 000) ✓
= - 2 000 N
Fnet= 2 000 N ✓ west ✓
✓Any one
Note: p and v must have the same sign

OPTION 3
Δx =(v1  + vfΔt
             2
=480 + 80(0.01)
        2
= 2,80 m
vf2 = vi2 + 2aΔx
(80)2 = (480)2 + 2a(2,80) ✓
a = - 40 000 m∙s-2
= ma ✓
= (0,05)(-40 000) ✓
= - 2 000 N
Fnet = 2 000 N ✓ west ✓

Wnet = ΔK ✓
Fnet Δxcosθ = ½mvf2 - ½mvi2
Fnet (2,80)cos0° ✓= ½(0,05)(802 - 4802) ✓
Fnet = -2 000 N
Fnet = 2 000 N ✓ west ✓

OR
Fnet (2,80)cos180° ✓ = ½(0,05)(802 - 4802) ✓
Fnet = 2 000 N ✓ west ✓ (5)
[10]

QUESTION 5
5.1 Note: -1 mark for each key word/phrase omitted in the correct context.
IF: The word "work" is omitted - 0 marks.
A conservative force is a force for which the work done (in moving an object between two points) is independent of the path taken. ✓✓
OR
A conservative force is a force for which the work done in moving an object in a closed path is zero.(2)
5.2 Gravitational (force) ✓
ACCEPT: Gravitation /Gravity/Weight (1)
5.3 No ✓
There is friction/non-conservative force (doing work)/It is not isolated system.✓
OR
The net work done by the non-conservative forces is not zero (2)
5.4 OPTION 1
EP = mgh ✓
= (1,8)(9,8) (1,5) ✓
= 26,46 J ✓

OPTION 2
Ww = -ΔEp ✓
(1,8)(9,8)(h – 0)cos180o = -(EpA – Ep(ground))
(1,8)(9,8)(1,5)(-1) = -EpA ✓
Ep = 26,46 J✓

OR
W = FΔxcosθ
= mgΔhcosθ
= (1,8)(9,8) (1,5)cos0o ✓
= 26,46 J✓ (3)
5.5 POSITIVE MARKING FROM QUESTION 5.4 
OPTION 1
Wnc = ΔK + ΔU
Wf = ½m(vf2 – vi2) + mg(hf – hi)
= ½(1,8)(42 – 0,952) ✓+ (0 – 26,46) ✓
= -12,87 J ✓

OPTION 2
Wnet = ΔK
Wf + Wg = ½mvf2 - ½mvi2
Wf + mgh = ½m(vf2- vi2)
Wf + mgh = ½mvf2 - ½mvi2
Wf + 26,46✓= ½(1,8)[(4)2 - (0,95)2] ✓
Wf = -12,87 J (- 12,872 J)✓

OPTION 3
E(mech)A = E(mech)B - Wf
(Ep + Ek)A = (Ep + Ek) B - Wf
(mgh + ½ mv2) A = (mgh + ½ mv2) B - Wf
26,46 + ½(1,8)(0,952) ✓ = 0 + ½(1,8)(42) - Wf ✓
Wf = -12,87 J ✓ (4)
5.6 Wnet = 0 (J ) / zero✓(1)
[13]

QUESTION 6
6.1 Doppler effect ✓(1)
6.2 (Q): (records sounds with) longer period/ longer time per wave / lower frequency.
OR
P: (records sounds with) shorter period/ shorter time per wave / higher frequency. ✓
ACCEPT
(Q): longer wavelength. /P: shorter wavelength. (1)
6.3 OPTION 1
f = ✓=    1     ✓ = 5,88 x 102 = 588,24 Hz ✓
    T       17 x 10-6

OPTION 2
speed =distance
                time
340 =   distance   
          25.5 x 10-6
Distance = 0,867 m
Distance = 1 ½ λ
∴λ = 0,578 m
v = fλ ✓
340 = f(0,578) ✓
f = 588,24 Hz ✓

OPTION 3
v = λ 
      T
340 =      λ      
         17 × 10-4
∴ λ = 0,578 m
v = fλ ✓
340 = f(0,578) ✓
f = 588,24 Hz ✓ (3)
6.4 POSITIVE MARKING FROM QUESTIONS 6.2 AND 6.3.
Do not penalise if 10-4 is again omitted.

OPTION 1
f =     1     = 5,56 x 102 = 555,56 Hz
    18 x 10-4
fL  = v ± vLfOR fL =   v    fs
        v ± v                v + vs
555,56 =   340    588.24
              340 + v
v = 20 m∙s-1
Range 19,57 – 20,09 m·s-1

OPTION 2
f =     1      
    18 x 10-4
fL  = v ± vLfOR  fL =   v     fs
        v ± v                  v + vs
      1       =     340           1    
18 x 10-4     340 + v  17 x 10-4
v = 20 m∙s-1
Range 19,57 – 20,09 m·s-1 (6)
[11]

QUESTION 7
7.1.1 Positive ✓ (1)
7.1.2 Marking criteria:

  • Appropriate formula 
  • Whole substitution
  • Final answer: 2,26 x 10-6 C ✓

OPTION 1
F=kQ1Q
       r
3.05 = (9 x 109)(6 x 10-6)Q
                     0.22
Q = 2,26 x 10-6 C ✓
(2,259 x 10-6 C)

OPTION 2
E = kQ
       r2
(9 x 109)(6 x 10-6)
               0.22
= 1,35 x 106 N·C-1
F = Eq✓
3,05 = (1,35 x 106)q✓
q = 2,26 x 10-6 N✓ (3)
7.1.3
19

Accepted labels
w Fg / Fw / weight / mg / gravitational force 
FT / tension / spanning 
FE/F  Electrostatic force/ Coulomb force/ FE Field/Fx on Y/ 3,05 N 

Notes

  • Mark is awarded for label and arrow. 
  • Do not penalise for length of arrows.
  • Deduct 1 mark for any additional force 
  • If force(s) do not make contact with dot: Max 32
  • If arrows missing: Max 32 (3)

7.1.4 Fnet = 0
FE = Tsin10°
F= Tcos80°
[3,05 = Tsin10°✓]✓ [IF Tcos10º = 3,05 (1/3)]
OR
[3,05 = Tcos80°✓]✓ [IF Tsin80º = 3,05 (1/3)]
T = 17,56 N  (17,564 N) (3)
7.2.1 Marking criteria

  • 1 mark for each key word/phrase omitted in the correct context.

The electric field at a point is the (electrostatic) force experienced per unit positive charge placed at that point. ✓✓
[IF the word “unit” or phrase “positive charge” is omitted in this definition: -1 for each
OR
The electric field at a point is the (electrostatic) force experienced by a UNIT positive charge placed at that point. ✓✓
[If “UNIT” is omitted in this definition, then 0 marks. (2)
7.2.2 OPTION 1
Electric field at M due to A (+2 x10-5 C):
EA = kQ 
         r2
= 9 x 109(2 x 10-6)
                  (0.2)2      
= 4,5 x106 N∙C-1
Electric field at M due to B (-4 x10-5 C):
EB = kQ     or     qB =2qA
         r2
= 9 x 109(4 x 10-6)    EB=2EA
                  (0.2)2
= 9 x106 N∙C-1 = 9 x 106 N∙C-1
Enet at M = EA + EB
= (4,5 x 106 + 9 x 106) ✓
= 1,35 x 107 N∙C-1 ✓ to the right/towards B/away from A

OPTION 2
Net electrostatic force at M
Fnet = kQ1Q kQ1Q
               r2                r2
= (9 x 109)(2 x 10-5)q  + (9 x 109)(4 x 10-5)q  (any one/ enige een)
               (0.2)2                         (0.2)2 
= 4,5 x 106q +✓ 9 x 106q
= 1,35 x 107q N
Fnet = Enetq ✓
1,35 x 107q ✓= Enetq
Enet = 1,35 x 107 N.C-1 ✓to the right ✓/towards B  (6)
[18]

QUESTION 8
8.1 (Maximum) energy provided (work done) ✓ by a battery per coulomb / unit charge passing through it. ✓
ACCEPT:
The reading on a voltmeter connected across a battery when there is no current/ in an open circuit.✓✓ (2)
8.2 13 V ✓ (1)
8.3.1 R =
                I
5.6 =10.5
           I
I = 1,88 A ✓ (1,875 A)
Marking criteria:

  • Appropriate formula ✓
  • Whole substitution✓
  • Final answer: 1,88 A ✓ (3)

8.3.2 POSITIVE MARKING FROM QUESTION 8.3.1.
OPTION 1
P = VI ✓
= (10,5)(1,88) ✓
= 19,74 W ✓ (19,688 W)

OPTION 2
P = I2R ✓
= (1,88)2(5,6) ✓
= 19,79 W ✓ (19,688 W)

OPTION 3
P =  V2
       R
=10.5
   5.6
= 19,69 W ✓ (19,688 W) (3)
8.3.3 POSITIVE MARKING FROM QUESTIONS 8.2 AND 8.3.1.
OPTION 1
Ɛ = I(R + r) ✓
13 = 1,88 (5,6 + r) ✓
r = 1,31 Ω  (1,31 – 1,33 Ω)

OPTION 2
r = Vinternal✓
            I
= 2.5  
  1.88
= 1,33 Ω ✓ ( 1,31 – 1,33 Ω)

OPTION 3
Ɛ = Vext + Vint
13 = 10,5 + Vint
Vint = 2,5 V
Vint = Ir ✓
2,5 = (1,88)r✓
r = 1,31 Ω ✓ (1,31 – 1,33 Ω) (3)
8.4.1 Decreases ✓
Vinternal resistance ✓
Vinterne weerstand (2)
8.4.2 Marking criteria

  • Formula Ɛ = I(R + r) ✓
  • Correct substitution into Ɛ = I(R + r) ✓
  • Substitution of values into Rp formula ✓
  • Halving value of R2X
  • Final answer: 1,49 Ω ✓ Range: 1,46 Ω – 1,49 Ω

POSITIVE MARKING FROM QUESTIONS 8.2 AND 8.3.3
OPTION 1
Ɛ = I(R + r) ✓
13 = 4 (Rext + 1,31) ✓
Rext = 1,94 Ω (1,92 Ω)
  1   =  1   +  1  
 RP     R1      R2
  1   =  1   +  1  
1.94   5.6    R2
R= 2.97Ω (2,92 Ω)
X= ½(2.97)
49,1 = Ω ✓ (1,46 – 1,49 Ω)

OPTION 2
Ɛ = I(R + r) ✓
13 = 4 (Rext + 1,31) ✓
Rext = 1,94 Ω (1,92 Ω)
RP =  R1 R2  
         R1 + R2 
1.94 =  5.6 R2 
           5.6 + R2
R2 = 2.97Ω (2,92 Ω)
X= ½(2.97)
49,1 = Ω ✓ (1,46 – 1,49 Ω)

OPTION 3
Ɛ = I(R + r) ✓
13 = 4 (Rext + 1,31) ✓
Rext = 1,94 Ω (1,92 Ω)
  1   =  1   +  1  
 RP     R1      R2
  1   =  1   +  1  
1.94   5.6    2X
X 49,1 = Ω ✓ (1,46 – 1,49 Ω)

OPTION 4
Ɛ = I(R + r) ✓
13 = 4 (Rext + 1,31) ✓
Rext = 1,94 Ω (1,92 Ω)
RP =  R1 R2  
         R1 + R2 
1.94 =  5.6(2X)  
           5.6 + 2X
X 49,1 = Ω ✓

OPTION 5
Ɛ = I(R + r) ✓
Vext = 13 – (4)(1,31) ✓
= 7,76 V
Vp = IR5,6
7,76 = I(5,6)
I5,6Ω = 1,37 A
IT = I2X + I5,6
4 = I2x + 1,37
I2X = 2,63 A
V = IR2X
[7,76 = (2,63)2X✓]✓
X = 1,46 Ω

OPTION 6
Ɛ = I(R + r) 
Vext = 13 – (4)(1,31) ✓
Vext = 7,76 V
I5,6Ω = 7.76 = 1,39 A
            5.6
I2x = 4 – 1,39 = 2,61 A
V2x = I2XR2X
[7,76 = (2,61)2X✓]✓
2X = 2,97 Ω
X = 1,49 Ω✓
VX = IXRX
3,88=(2,61)RX✓
RX = 1,49 Ω✓

OPTION 7
Ɛ = I(R + r)✓
Vext = 13 – (4)(1,31)✓
= 7,76 V
Vext = IRext
7,76 = (4)( +)-1
                2X   5.6
X = 1,48 Ω ✓ (5)
[19]

QUESTION 9
9.1
9.1.1 DC ✓ (1)
9.1.2 NOTE: -1 mark for each key word/phrase omitted in correct context.
Emf is induced as a result of change of magnetic flux (linked) with the coil. ✓✓(2)
9.1.3 POSITIVE MARKING FROM QUESTION 9.1.1
20
9.2.1 The AC potential difference/voltage which dissipates the same amount of energy ✓ as DC potential difference. ✓
OR
(The rms value of AC is) the DC potential difference/voltage which dissipates the same amount of energy ✓ as AC potential difference/voltage. ✓(2)
9.2.2
21
(5)
[12]

QUESTION 10
10.1 Note: -1 mark for each key word/phrase omitted in correct context.
The process whereby electrons are ejected from a metal / surface when light (of suitable frequency) is incident on that surface. ✓✓ (2)
10.2 7,48 x 10-19 (J) ✓
E = Wo + Ek(max) (= Wo + ½mv2max) ✓
When Ek(max) = 0 / v = 0 / v2 = 0 / E = Wo / Wo is the y-intercept ✓ (3)
10.3 Mass (of photo-electron) ✓
ACCEPT :½m (1)
10.4 OPTION 1
Gradient = ½m
11.98 x 10-19 - 7.48 x 10-19 = ½(9,11 x 10-31) ✓
             X - 0
X = 0,9879 ✓ (0,99 or 0,988)
ACCEPT
X = 0,9879 x 1012 (m2∙s-2)

POSITIVE MARKING FROM 10.2
OPTION 2
E = Wo + Ek(max)
E = Wo + ½mv2(max)
11,98 x 10-19 ✓ = 7,48 x 10-19 ✓+ ½(9,11 x 10-31) v2✓ [or ½(9,11 x 10-31)X]
4,5 x 10-19 = 4,56 x 10-31v2
v2 = 0,9868 x 1012
X/v2 = 0,9868 ✓ (0,99)
Range (0,9868 – 0,9879 / 9,87 x 1011 – 9,88 x 1011)

ACCEPT:
X = 0,9868 x 1012 (m2∙s-2) / 9,868 x 1011 (m2∙s-2) (5)
10.5.1 Remains the same ✓ (1)
10.5.2 Increases ✓ (1)
[13]
TOTAL: 150

Last modified on Thursday, 02 December 2021 09:31