GCSE Physics: Forces — Topic Revision Workbook

Inside GCSE Physics: Forces — Topic Revision Workbook

tell scalars from vectors and sort contact from non-contact forces, calculate weight with W = mg and describe resultant and free-body forces, work through distance, speed, velocity and acceleration with a = Δv/t and read distance–time and velocity–time graphs, apply Newton's three laws with F = ma, work done W = Fs and Hooke's law F = ke, then master stopping distance and momentum before an exam-style application task. About 30 minutes.

Learning objectives

• scalars and vectors and the difference between contact and non-contact forces, plus weight with W = m × g;
• motion — distance and displacement, speed and velocity, acceleration a = Δv ÷ t, and reading distance–time and velocity–time graphs;
• Newton's three laws, resultant and free-body forces, and Newton's second law F = m × a;
• work done W = F × s and elasticity with Hooke's law F = k × e;
• stopping distance (thinking + braking distance and the factors affecting each) and momentum p = m × v.

Activities in this book

1. Task 1 — Forces, Scalars & Vectors

   a scalar has size only (mass, speed, distance, energy); a vector has size and direction (force, weight, velocity, acceleration). Contact forces need surfaces to touch (friction, air resistance, tension, normal contact); non-contact forces act at a distance (gravitational, magnetic, electrostatic). Weight is the force of gravity on a mass: W = m × g, with g ≈ 9.8 N/kg (you may use 10).

2. Task 2 — Motion, Speed & Graphs

   distance is a scalar; displacement is the vector version (straight line plus direction). Speed is a scalar; velocity is speed in a given direction. Acceleration a = Δv ÷ t, measured in m/s². On a distance–time graph the gradient is the speed; on a velocity–time graph the gradient is the acceleration and the area under the line is the distance travelled.

3. Task 3 — Newton's Laws, Work & Elasticity

   the resultant force is the single force left after adding forces along a line. Newton's 1st law: velocity stays constant unless a resultant force acts. Newton's 2nd law: F = m × a. Newton's 3rd law: every action has an equal and opposite reaction. Work done W = F × s (joules). Hooke's law F = k × e applies up to the limit of proportionality.

4. Task 4 — Stopping Distance & Momentum

   stopping distance = thinking distance + braking distance. Thinking distance grows with reaction time (tiredness, alcohol, drugs, distractions) and speed; braking distance grows with speed, and with a wet or icy road, worn tyres or worn brakes. Momentum p = m × v (kg m/s) is a vector, conserved in collisions.

5. Task 5 — Exam-Style Application

   exam questions reward joined-up physics: quote the equation, substitute with units, then explain the idea in words. For a 6-mark question, plan three or four clear points, use the correct key terms, and answer every part of the question.

Suggestions for teaching

• Equations first. Get learners to write the equation, substitute the numbers with units, then calculate — exactly as the mark scheme rewards.
• Vectors vs scalars. Keep sorting quantities into scalar (size only) and vector (size and direction) until it is automatic.
• Read the graphs. Drill that a distance–time gradient gives speed, while a velocity–time gradient gives acceleration and the area gives distance.
• Free-body thinking. Model resultant force and terminal velocity with weight down and air resistance up, so learners can explain motion in words.