Physics Insight

Question pattern · Knowledge card

Position–time graph analysis

Read position from the vertical axis and velocity from graph gradient; changes in gradient describe changes in velocity rather than changes in position alone.

Primary skill
Calculate & apply
Original practice questions
2

Connect the ideas

Key relationships and graph reading

  • Average velocity = secant gradient Δx / Δt
  • Instantaneous velocity = tangent gradient
  • A horizontal position–time segment means the object is at rest

Check your method

Three common mistakes

  1. Reading graph height as velocity.
  2. Calling a horizontal segment zero position.
  3. Ignoring negative gradient when the object reverses direction.

Original micro-example

Try the idea in miniature

A straight position–time segment runs from x = 2 m at t = 1 s to x = 8 m at t = 4 s.

Show the short answer

Its velocity is the gradient: (8 − 2) / (4 − 1) = +2 m s⁻¹.

Original practice questions

Practise this question pattern

The pattern describes the reasoning structure. Each link below opens a distinct original practice question.