This key facts covers Newton's Second Law — F = ma within Newton's Laws of Motion for GCSE Physics. Revise Newton's Laws of Motion in Forces for GCSE Physics with 24 exam-style questions and 15 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 4 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
📜 Newton's Second Law — F = ma
What this means:
- Acceleration is proportional to force (double F → double a)
- Acceleration is inversely proportional to mass (double m → half a)
- Acceleration is in the same direction as the resultant force
Rearrangements:
- a = F / m (to find acceleration)
- m = F / a (to find mass)
Key insight: This is why heavy objects are harder to accelerate — same force, more mass, less acceleration.
Practice questions for Newton's Laws of Motion
According to Newton's First Law, what happens to an object when there is no resultant force acting on it?
A spaceship is travelling through deep space far from any planets. The engines are switched off. Explain what will happen to the motion of the spaceship and why.