Common IB Mistakes in Forces and Motion
Forces and motion is one of the most technical areas in IB Sports, Exercise and Health Science (SEHS). While many students understand the basic ideas, marks are often lost due to incorrect application, vague explanations, or confusion between related concepts. Identifying common mistakes helps students refine their answers and improve exam performance.
IB examiners reward clarity, correct terminology, and applied understanding.
Confusing Force with Motion
One of the most frequent mistakes is confusing force with motion. Force causes changes in motion, but force itself is not motion.
Common errors include:
- Saying force is speed
- Saying force is acceleration
- Assuming movement requires constant force
High-mark answers clearly explain that force causes acceleration or changes in motion, not motion itself.
Misapplying Newton’s Laws
Students often memorise Newton’s laws but struggle to apply them correctly.
Typical mistakes include:
- Using the wrong law for a scenario
- Describing Newton’s First Law when acceleration is involved
- Forgetting the role of mass in Newton’s Second Law
In IB SEHS, students should match each law to the correct sporting situation and explain how it applies.
Ignoring Direction of Forces
Another common issue is failing to consider force direction. Forces are vectors, meaning direction matters.
Examples of mistakes include:
- Explaining force size but not direction
- Ignoring horizontal and vertical components
- Applying force in the wrong direction for movement
High-mark answers explain how force direction influences acceleration, movement path, or stability.
Poor Use of Sporting Examples
Many students use vague or unrealistic examples when explaining forces.
Weak examples include:
- “An athlete pushes harder”
- “More force is used”
Strong answers:
- Name a specific movement
- Explain how force is applied
- Link force to performance outcome
Clear sporting examples demonstrate applied understanding.
Overusing Formulas Without Explanation
IB SEHS does not reward formula memorisation alone. Students often lose marks by writing equations without explaining them.
Examiners expect:
- Conceptual explanations
- Clear links to movement or performance
- Correct use of terminology
Formulas should support explanations, not replace them.
How to Avoid These Mistakes
To improve forces and motion answers:
- Focus on cause-and-effect explanations
- Always link force to changes in motion
- Apply concepts to real sporting situations
Practising applied explanations is more effective than memorising definitions.
RevisionDojo Call to Action
If forces and motion questions feel technical or inconsistent, RevisionDojo helps IB SEHS students master biomechanics with clear explanations, applied examples, and exam-style practice. It is the most effective way to turn confusion into exam confidence.
Frequently Asked Questions (FAQs)
Why do students lose marks on forces and motion questions?
Marks are often lost due to vague explanations, incorrect application of laws, or lack of sporting context.
Do I need to use formulas in IB SEHS exams?
Formulas are helpful, but clear explanations and application are more important for earning marks.
How can I improve my forces and motion answers?
Regular exam-style practice focusing on explanation, direction of force, and application is key.
