This common misconceptions covers Common Misconceptions within Newton's Laws of Motion for GCSE Physics. Revise Newton's Laws of Motion in Forces for GCSE Physics with 13 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 10 of 15 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 10 of 15
Practice
13 questions
Recall
15 flashcards
⚠️ Common Misconceptions
Misconception 1: "Weight and normal force are a Newton's Third Law pair"
They are NOT a Third Law pair! Both weight and normal force act on the SAME object (the book on the table). A true Third Law pair: the book pulls the Earth upward with a gravitational force equal to the book's weight, and the Earth pulls the book downward. For the table: the book pushes the table downward, and the table pushes the book upward — that IS a Third Law pair.
Misconception 2: "If two forces are equal and opposite, they must be a Third Law pair"
Not necessarily! Weight and normal force on a book are equal and opposite but are NOT a Third Law pair (same object, different types of force — gravity vs contact). True Third Law pairs: same type of force, different objects, always equal and opposite.
Misconception 3: "F = ma means more force always means more speed"
F = ma links force to ACCELERATION (rate of change of velocity), not speed directly. A force in the OPPOSITE direction to motion causes deceleration, reducing speed. The direction of the resultant force determines the direction of acceleration — which may increase or decrease speed.