Matric Physical Sciences — Questions and Answers
Question 1: What is the SI unit of force?
- Joule
- Newton (Correct answer)
- Watt
- Pascal
Correct answer: Newton
Force is measured in newtons (N), defined as the force that gives a 1 kg mass an acceleration of 1 m·s⁻².
Question 2: An object of mass 5 kg accelerates at 2 m·s⁻². What is the net force acting on it?
- 10 N (Correct answer)
- 2.5 N
- 7 N
- 3 N
Correct answer: 10 N
Newton's second law: F = ma = 5 × 2 = 10 N.
Question 3: Which of the following is the chemical formula for water?
- CO₂
- H₂O₂
- H₂O (Correct answer)
- OH
Correct answer: H₂O
Water consists of two hydrogen atoms and one oxygen atom, written as H₂O.
Question 4: What type of bond forms between a metal and a non-metal through the transfer of electrons?
- Ionic bond (Correct answer)
- Covalent bond
- Metallic bond
- Hydrogen bond
Correct answer: Ionic bond
Ionic bonds form when electrons transfer from a metal to a non-metal, creating oppositely charged ions that attract.
Question 5: Calculate the work done when a force of 20 N moves an object 4 m in the direction of the force.
- 5 J
- 24 J
- 16 J
- 80 J (Correct answer)
Correct answer: 80 J
Work = force × distance = 20 × 4 = 80 J.
Question 6: What is the acceleration due to gravity near the Earth's surface (used in Grade 12)?
- 9.8 m·s⁻² (Correct answer)
- 10 m·s⁻¹
- 98 m·s⁻²
- 1.8 m·s⁻²
Correct answer: 9.8 m·s⁻²
The value of gravitational acceleration used in the NSC syllabus is 9.8 m·s⁻² directed downwards.
Question 7: In the reaction 2H₂ + O₂ → 2H₂O, what is the type of reaction?
- Decomposition
- Synthesis (combination) (Correct answer)
- Displacement
- Neutralisation
Correct answer: Synthesis (combination)
Two reactants combine to form a single product, which is a synthesis (combination) reaction.
Question 8: Which quantity is a vector?
- Speed
- Distance
- Velocity (Correct answer)
- Mass
Correct answer: Velocity
Velocity has both magnitude and direction, making it a vector. Speed, distance and mass are scalars.
Matric Physical Sciences
What is the SI unit of force?