Library › Mechanics 1 WME01 › Kinematics Graphs

AS Level · Mechanics 1 WME01

Kinematics Graphs

Revise Kinematics Graphs for Mechanics 1 WME01 (AS Level) — revision notes and instant AI marking.

📖 Revision notes · preview

Edexcel IAL Mechanics 1

Kinematics Graphs

Motion can be read like a story — every slope, every flat line, every area tells you exactly what an object is doing. Master this and exams become a translation exercise.

4 Topics Worked Examples Concept Checklist Exam Tips

💡 The Big Idea: The gradient of a graph gives you the next quantity down (displacement → velocity → acceleration), and the area under a graph gives you the previous quantity back up. Everything else follows from this.

Overview

Chapter Summary

Displacement–Time (s–t): Gradient = velocity. Horizontal line = stationary. Curve = changing velocity.

Velocity–Time (v–t): Gradient = acceleration. Area = displacement. Below x-axis = moving backwards.

Acceleration–Time (a–t): Area = change in velocity. Can't read velocity directly — need initial velocity too.

Drawing Graphs: Label axes + units, mark key points, draw section by section. Gradient and area let you work backwards.

Scalars vs Vectors: Speed & distance ≥ 0 always. Velocity & displacement can be negative (direction matters).

Average measures: Avg speed = total distance ÷ time. Avg velocity = displacement ÷ time.

Topic 1

Displacement–Time Graphs

What is it?

A displacement–time graph plots an object's displacement from a fixed origin (y-axis) against time (x-axis). Unlike a distance–time graph, it can dip below the x-axis — because displacement can be negative (think: 10 m to the left of where you started).

📏 Distance

Scalar — how far travelled in total.
Always ≥ 0. Never negative.

↔ Displacement

Vector — position relative to start.
Can be negative (going backwards).

Key Features — What Each Shape Means

Positive gradient (line going up): moving forwards — positive velocity.
Negative gradient (line going down): moving backwards — negative velocity.
Steeper line: greater speed (larger |gradient|).
Straight line: constant velocity (no acceleration).
Curved line: accelerating or decelerating (velocity is changing).
Horizontal line: stationary — velocity = 0.
Graph touches x-axis: the object is at the origin at that moment.
Graph below x-axis: the object is on the other side of the origin.

Core Rule

Velocity = Gradient of s–t graph = Δs / Δt

Pick two points on any straight segment → rise ÷ run = velocity (with sign!)

Average Speed & Velocity

Average Speed = Total Distance Travelled ÷ Time Taken

Average Velocity = Displacement from Start ÷ Time Taken

🧠 Why can average speed ≠ average velocity? Imagine jogging 100 m forward then 60 m back in 40 s. Total distance = 160 m, so avg speed = 4 m/s. But displacement = 40 m, so avg velocity = 1 m/s. The graph goes up then comes back down.

Worked Example — Athlete's Displacement–Time Graph

An athlete jogs in a straight line. On the graph: displacement rises from 0 to 5 m in the first 2 s, stays flat at 5 m from t = 2 to t = 5 s, rises to 11 m at t = 8 s, then falls back to 0 m at t = 14 s.

(a) Velocity in first 2 seconds:

Velocity = gradient = Δs / Δt = (5 − 0) / (2 − 0) = 2.5 ms⁻¹

(b) Motion between t = 2 s and t = 5 s:

The graph is horizontal (flat). Gradient = 0 → velocity = 0. The athlete is stationary.

−1.83 ms⁻¹

🔓 Read the full Kinematics Graphs note → You're seeing the preview · sign in to read it all

Also in the full note

How to Draw Any Kinematics Graph
Quick Reference — Graph Interpretation

What's inside

📖 Revision notes 🎯 Learn mode ✦ AI flashcards ✓ Instant AI marking 🧊 3D explorers 🧪 Experiments & simulations 📈 Progress tracking

📄 Practise Kinematics Graphs with Mechanics 1 WME01 past papers Every paper with its mark scheme — answer online, marked instantly. Open →

Read the full Kinematics Graphs notes free

That's the preview — create a free account to read the rest, plus flashcards and practice questions with instant AI marking. No credit card.

Unlock the full notes free →

Kinematics Graphs

Kinematics Graphs

What is it?

Key Features — What Each Shape Means

More Mechanics 1 topics