TECHNICAL SCIENCES
PAPER 1
GRADE 12 
NSC EXAMS
PAST PAPERS AND MEMOS JUNE 2019

MEMORANDUM 

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

QUESTION 2 
2.1
2.1.1 
 (4)  
2.1.2

• fk = µkN ✓
  fk = (0,2)(20)(9,8) ✓✓ 
   = 39,2 N West ✓ (4)    

 2.1.3

• F_net = fk + Fgirl✓ 
  = (-39,2) ✓ + ( 50) ✓ 
  = 10,8 N east ✓ (4)    

 2.1.4

• When a net force acts on an object of mass m, it accelerates the  object in the direction of the net force. This acceleration is directly  proportional to the net force and inversely proportional to the  mass of the object. ✓✓  (2)    

2.1.5

• F_net = ma ✓
  10,8 = (20)a ✓
  a = 0,54 m.s^-2 ✓ (3)    

2.2
2.2.1 Decreases ✓ (1)    
2.2.2 Increases✓ (1)    
2.2.3 Increases✓ (1)   [20]   

QUESTION 3 
3.1
3.1.1 When object A exerts a force on object B, object B  simultaneously exerts an oppositely directed force of equal  magnitude on object A. ✓✓  (2)    
 3.1.2 100 N due west  ✓✓ (2) 
3.2
3.2.1 Box thrown backward  ✓✓ (2)  
3.2.2 The box opposes a change in its state of rest ✓ due to its  inertia ✓ according to Newton’s first law of motion. ✓  (3)   [9]   

QUESTION 4  
4.1
4.1.1 Impulse is the product of the net force acting on an object and the  time the net force acts on the object. ✓✓  (2)  
4.1.2 Vector ✓ (1)  
 4.1.3

• Impulse = ∆p or Impulse = m∆v ✓
  Impulse = (1 500)(0 – 14) ✓✓ 
  = (- 21 000 N.s ✓ (kg.m.s^-1) 
  = 21 000 N.s away from the barrier (4)  

 4.1.4

• F_net = Δp ✓
             Δt
  F_net =-21000
                0,5  
  F_net = -42 000 N ✓ (3)  

 4.1.5

• Crumple zone helps the car to take a longer time to come to a  stop ✓. F_net∆t = ∆p, the longer the time interval, the smaller the  net force acting for the same ∆p ✓. 
  ∴ the injuries are minimised. ✓  (3)  

4.2
4.2.1 Momentum is defined as the product of an object's mass and its  velocity. ✓✓  (2)  
 4.2.2

• Elastic collision: A collision in which both the momentum and  kinetic energy are conserved. ✓✓
• Inelastic collision: A collision in which only the momentum is  conserved.✓✓ (4)  

 4.2.3

• The total linear momentum of an isolated system remains  constant (is conserved). ✓✓  (2)  
  OR 
• Total linear momentum before collision is equal to the total linear  momentum after the collision in an isolated system. ✓✓ 

 4.2.4

• Σp_before = Σp_after 
  mAvA_initial + mBvB_initial = mAvA_final + mBvB_final ✓ Any ONE
  (800)(0) + (1000)(33) ✓ = (800)(17) + (1000)(v) ✓
  v = 19,4 m.s^-1 ✓ (4)    

 4.2.5 Inelastic ✓ (1)   [26]    

QUESTION 5
5.1
5.1.1 Work done is defined as the product of the force acting on an  object and the displacement in the direction of the force. ✓✓  (2)  
 5.1.2

• W = F∆x cos θ ✓
  W = (200)(5) cos 20° ✓
  W = 939,69 J ✓ (3)  

5.1.3 0 ✓ (J) (1)  
5.1.4 Box moves with constant velocity. ✓ Net force is zero. ✓ (Hence  the net work done is 0 J.)  (2)  
5.1.5

• No. ✓ Force of gravity is perpendicular to the direction of  motion.✓✓
  OR
• W = F∆xcosθ ✓ 
  = F∆xcos90o ✓
  = 0 J ✓ (3)  

5.2
5.2.1 Power is defined as the rate at which work is done OR rate at  which energy is expended. ✓✓  (2)  
5.2.2

• P =  w  ✓ 
         Δt
  P =  (2000)(9,8)(20)
                    60
  P = 6533,33 W ✓
  P = 6533,33 = 8,76 hp / pk ✓ (4)  
            746

5.3
5.3.1 Sum of gravitational potential energy and kinetic energy. ✓✓✓✓ (2)  
5.3.2 Energy possessed by an object due to its position above the  ground. ✓✓  (2)  
5.3.3 (a) Increases✓ (1)   (b) Remains the same✓ (1)  
5.3.4 The total mechanical energy in an isolated system remains  constant. ✓✓  (2)  
5.3.5

• M_E (B) = mgh + ¹/₂ mv² ✓ 
  = m(9,8)(1,5) + ¹/₂m(8)² ✓ 
  = 46,7 m ✓
• M_E(A) = mgh + ¹/₂mv² 
   = m(9,8)h + 0 ✓ 
  = 9,8 mh ✓
• M_E (A) = M_E(B) ✓
  9,8 mh = 46,7 m 
  h = 4,77 m ✓ (7)   [32]   

QUESTION 6 
6.1

• A perfectly elastic body: A body which regains its original shape and size  completely when the deforming force is removed. ✓✓
• A perfectly plastic body: A body that does not show a tendency to regain  its original shape and size when the deforming force is removed. ✓✓   (4)    

6.2 Hooke’s law: Within the limit of elasticity, ✓ stress is directly proportional to  the strain.✓  (2)    
6.3
6.3.1 Stress is internal restoring force per unit area of a body. ✓✓ (2)    
6.3.2

• σ = F
        A
  σ =   200     
        5 × 10^-5 ✓
  σ = 4 000 000 Pa ✓ (3)    

 6.3.3

• K = σ ✓ 
         ε
  4 × 108 ✓ = 4 000 000
                           ε
  ε = 0,01 
  ε = Δl
        L
  0,01 = Δl ✓
             2
  ∆l = 0,02 m ✓
  Final length e = 2 + 0,02 = 2,02 m ✓ (6)   [17]   

QUESTION 7  
7.1 Viscosity is defined as the property of a fluid to oppose relative motion  between the two adjacent layers. ✓✓   (2)    
7.2
7.2.1 Winter ✓✓ (2)    
7.2.2 10W40 ✓✓ (2)    
7.2.3 5W40 ✓✓ (2)    
7.3
7.3.1 Pascal's law: In a continuous liquid at equilibrium, the pressure  applied at a point is transmitted equally to the other parts of the   liquid. ✓✓ (2 OR 0)  (2)    
7.3.2  

• F₁ = F₂  ✓ 
  A₁    A₂
         100     =   1200   
  1,2 × 10^-3          A₂
  A₂ = 0,014 m² ✓ (3)    

 7.3.3 Increase the area of piston B. ✓✓ (2)    
 7.3.4 Bulldozer's working systems, hydraulic power brakes on  automobiles, dentists' chairs, hydraulic lifts used to lift heavy loads,  car jacks, or any other correct application. (ANY THREE) ✓✓✓  (3)  [18]   

QUESTION  8 
8.1 An intrinsic semiconductor is a pure semiconductor. ✓✓  (2)    
8.2 Doping is the process of adding impurities to intrinsic semiconductors. ✓✓ (2)    
8.3 Phosphorous or arsenic✓✓ (2)    
8.4 Negative charge/negatiewe lading ✓✓ (2)   Electron [8]   

TOTAL: 150