Cambridge IGCSE 0625: Forces, Resultant Force & Newton’s Three Laws | Tutolia Study Library
Master balanced vs unbalanced forces, Hooke’s law, spring constants, terminal velocity, and F=ma calculations for Cambridge IGCSE 0625.
Subject: Physics | Grade Level: Grade 9-10 (IGCSE) | Curriculum: Cambridge IGCSE
Cambridge IGCSE: Forces, Resultant Force & Newton’s Three Laws (Physics)
Syllabus Code: 0625 · Topic Code: 1.5 · Level: Grade 9-10 (IGCSE)
Aligned with official Cambridge IGCSE examination standards and assessment objectives.
🎯 Official Syllabus Learning Objectives
Candidates should be able to:
- [x] State that an unbalanced force causes acceleration, deceleration, or change in direction
- [x] Recall and apply F = ma and Hooke’s law F = kx up to limit of proportionality
- [x] Describe how terminal velocity is achieved when air resistance balances weight
📐 Essential Formulas & Mathematical Equations
$
F_{\text{net}} = m \cdot a
$
$
F = k \cdot x
$
💡 Conceptual Breakdown & Core Revision Notes
Mastering Forces, Resultant Force & Newton’s Three Laws is critical for scoring Grade 9 / A* in Cambridge IGCSE Physics. When preparing for exam papers, examiners prioritize precise definitions, proper scientific command-word execution (State, Describe, Explain, Evaluate), and dimensional unit consistency.
Methodical Problem-Solving Framework
- List Given Variables: Write down all given quantities with their respective SI units and identify the target variable.
- Standardise Units: Always convert non-standard units (e.g. grams to kilograms, centimeters to meters, cm³ to dm³, hours to seconds).
- State the Base Formula: Always state the general equation explicitly before substituting numbers to secure method marks.
- State Final Value with Units: Quote your final calculated value to the required number of significant figures (typically 2 or 3 significant figures in Cambridge & IB) followed by the correct unit.
⚠️ Examiner Warnings & Common Student Pitfalls
Chief Examiner Advice:
At terminal velocity, acceleration is ZERO because resultant force is zero. Velocity is NOT zero; it is at its constant maximum.
📝 Worked Exam Exemplar (Mark Scheme Breakdown)
Question:
A skydiver of total mass 80 kg experiences an air resistance of 600 N. Taking g = 9.8 m/s², calculate the downward acceleration.
Model Answer & Marking Rubric:
Weight W = 80 * 9.8 = 784 N. Resultant force = 784 - 600 = 184 N downwards. a = F / m = 184 / 80 = 2.3 m/s².
🧠 Rapid Active-Recall Study Deck (Spaced Repetition)
Test your immediate retention before leaving this page:
- Question: What is the fundamental definition associated with Forces, Resultant Force & Newton’s Three Laws?
Answer: Check the primary learning objective in the checklist above.
- Question: Which governing formula links the main physical quantities in this topic?
Answer: `F_{\text{net}} = m \cdot a`.
- Question: What classic trap do examiners frequently set on this topic?
Answer: At terminal velocity, acceleration is ZERO because resultant force is zero. Velocity is NOT zero; it is at its constant maximum.