Level 4 · Science S4.8

Newton's laws

Three laws explain how forces change the motion of everything from a ball to a bus.

Planned. This book is not written yet. Below is its plan, which a teacher can already use.

You are ready for this book if

You can calculate a speed from a distance and a time.

The plan

  1. S4.8.1 Scalars and vectors
    • Sort quantities into scalars and vectors
    • Find the resultant of two forces along a line
    • Add two forces at right angles with a scale drawing
  2. S4.8.2 Velocity and acceleration
    • Calculate acceleration from change in velocity and time
    • Find acceleration and distance from a velocity and time graph
  3. S4.8.3 Newton's first law
    • Explain why an object keeps moving unless a resultant force acts
    • Explain how seat belts protect passengers using inertia
  4. S4.8.4 Newton's second law
    • Use force equals mass times acceleration in calculations
    • Explain why a loaded truck speeds up more slowly than an empty one
  5. S4.8.5 Weight and falling
    • Calculate weight from mass and gravitational field strength
    • Explain terminal velocity using the forces on a falling object
    • Time paper cones falling to show terminal velocity
  6. S4.8.6 Newton's third law
    • Identify force pairs in walking, swimming and rockets
    • Explain why the two forces in a pair act on different objects
  7. S4.8.7 Momentum
    • Calculate momentum and use its conservation in collisions
    • Explain how crumple zones and helmets reduce force by increasing time
  8. S4.8.8 Stopping distances
    • Explain what affects thinking distance and braking distance
    • Use a measured reaction time to work out thinking distance

For parents and teachers

Level 4 fits learners who can already: follow a written argument. use letters for numbers. In many schools that is about 14 to 16, but start wherever the learner is.

Strand: Forces and motion. Written and drawn by attnom. Free to read, print and share.