IGCSE Physics Motion: Complete Guide for Cambridge IGCSE Physics (0625)

Motion is one of the most fundamental topics in Cambridge IGCSE Physics (0625). Understanding speed and velocity, acceleration, motion graphs, and freefall is essential for mastering kinematics and achieving top grades in your IGCSE Physics exams.

This comprehensive IGCSE Physics Motion guide covers everything you need to know, including speed vs velocity, acceleration calculations, distance-time and speed-time graphs, freefall mechanics, step-by-step worked examples, common exam questions, and expert tips from Tutopiya’s IGCSE Physics tutors. We’ll also show you how to avoid the most common mistakes that cost students valuable marks.

🎯 What you’ll learn: By the end of this guide, you’ll know how to calculate speed, velocity, and acceleration, interpret and draw motion graphs, solve freefall problems, and apply these skills confidently in IGCSE Physics exams.

Already studying with Tutopiya? Practice these skills with our dedicated IGCSE Physics Motion practice deck featuring exam-style questions, videos, and instant feedback.

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Why Motion Matters in IGCSE Physics

Motion is a cornerstone topic that appears throughout the IGCSE Physics syllabus. Here’s why it’s so important:

• High exam frequency: Motion questions appear in almost every IGCSE Physics paper
• Exam weight: Typically worth 10-15 marks per paper, making it crucial for grade boundaries
• Foundation for advanced topics: Essential for understanding forces, energy, and momentum
• Graphical skills: Develops critical graph interpretation and drawing skills
• Real-world applications: Used in transportation, sports science, engineering, and everyday life
• Practical connections: Links theory to practical experiments and real-world scenarios

Key insight from examiners: Students often lose marks not because they don’t understand the concepts, but because they confuse speed with velocity, misread graphs, or forget units. This guide will help you avoid these pitfalls.

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Speed and Velocity: The Fundamental Difference

Understanding the difference between speed and velocity is crucial for IGCSE Physics. While they’re related, they’re not the same thing.

What is Speed?

Speed is a scalar quantity that measures how fast an object is moving, without regard to direction.

Key characteristics of speed:

• Scalar quantity (magnitude only, no direction)
• Always positive (or zero)
• Measured in units like m/s, km/h, or mph

Speed Formula:

Speed = Distance ÷ Time

Where:

• Speed is measured in metres per second (m/s) or kilometres per hour (km/h)
• Distance is measured in metres (m) or kilometres (km)
• Time is measured in seconds (s) or hours (h)

Example: A car travels 100 km in 2 hours.
Speed = 100 km ÷ 2 h = 50 km/h

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What is Velocity?

Velocity is a vector quantity that measures the speed in a specific direction.

Key characteristics of velocity:

• Vector quantity (has both magnitude and direction)
• Can be positive or negative (depending on direction)
• Must include direction in the answer

Velocity Formula:

Velocity = Displacement ÷ Time

Where:

• Velocity is measured in metres per second (m/s)
• Displacement is the straight-line distance from start to finish with direction
• Time is measured in seconds (s)

Example: A car travels 100 km north in 2 hours.
Velocity = 100 km north ÷ 2 h = 50 km/h north

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Speed vs Velocity: The Key Difference

Aspect	Speed (Scalar)	Velocity (Vector)
Direction	No direction needed	Direction required
Type	Scalar quantity	Vector quantity
Formula	Distance ÷ Time	Displacement ÷ Time
Example	”50 m/s"	"50 m/s east” or “-50 m/s”
Values	Always positive	Can be positive or negative

Common Confusion to Avoid

❌ Wrong: “The car’s speed is 60 m/s north”
✅ Correct: “The car’s velocity is 60 m/s north” or “The car’s speed is 60 m/s”

❌ Wrong: “Speed has direction”
✅ Correct: “Speed has no direction; velocity has direction”

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Average Speed and Instantaneous Speed

Average Speed

Average speed is the total distance traveled divided by the total time taken for the entire journey.

Formula:

Average Speed = Total Distance ÷ Total Time

Example: A car travels 60 km in the first hour, then 40 km in the next hour.
Total distance = 60 + 40 = 100 km
Total time = 2 hours
Average speed = 100 ÷ 2 = 50 km/h

Instantaneous Speed

Instantaneous speed is the speed at a specific moment in time. It’s what a speedometer shows.

Example: A car’s speedometer reading at a particular moment shows 65 km/h. This is the instantaneous speed.

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Worked Example 1: Calculating Speed

A cyclist completes a 1500 m race in 5 minutes. Calculate the cyclist’s average speed.

Solution:

1. Identify known values:

   • Distance = 1500 m
   • Time = 5 minutes = 5 × 60 = 300 s

2. Use the formula:

   • Speed = Distance ÷ Time
   • Speed = 1500 m ÷ 300 s = 5 m/s

3. Check units: Answer is in m/s, which is appropriate.

Answer: The cyclist’s average speed is 5 m/s.

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Worked Example 2: Speed with Unit Conversion

A car travels at 108 km/h. Express this speed in m/s.

Solution:

1. Convert km to m: 108 km = 108 × 1000 = 108,000 m
2. Convert h to s: 1 hour = 3600 s
3. Calculate: Speed = 108,000 m ÷ 3600 s = 30 m/s

Alternative method (faster):

• To convert km/h to m/s, divide by 3.6
• 108 ÷ 3.6 = 30 m/s

Examiner tip: Remember that 1 km/h = 1000 m ÷ 3600 s = 5/18 m/s ≈ 0.278 m/s
Or simply: km/h ÷ 3.6 = m/s

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Acceleration: Rate of Change of Velocity

Acceleration is the rate of change of velocity. It tells us how quickly an object’s velocity is changing.

Understanding Acceleration

Key points:

• Acceleration is a vector quantity (has direction)
• Positive acceleration means velocity is increasing
• Negative acceleration (deceleration) means velocity is decreasing
• Acceleration can occur even when speed is constant (change in direction)

Acceleration Formula

Acceleration = Change in Velocity ÷ Time Taken

Or:

a = (v - u) ÷ t

Where:

• a = acceleration (m/s²)
• v = final velocity (m/s)
• u = initial velocity (m/s)
• t = time taken (s)

Units: Acceleration is measured in metres per second squared (m/s²)

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Worked Example 3: Calculating Acceleration

A car accelerates from rest to 30 m/s in 10 seconds. Calculate the acceleration.

Solution:

1. Identify known values:

   • Initial velocity (u) = 0 m/s (from rest)
   • Final velocity (v) = 30 m/s
   • Time (t) = 10 s

2. Use the formula:

   • a = (v - u) ÷ t
   • a = (30 - 0) ÷ 10
   • a = 30 ÷ 10 = 3 m/s²

3. State answer: The car’s acceleration is 3 m/s².

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Worked Example 4: Deceleration (Negative Acceleration)

A car traveling at 25 m/s comes to rest in 5 seconds. Calculate the acceleration.

Solution:

1. Identify known values:

   • Initial velocity (u) = 25 m/s
   • Final velocity (v) = 0 m/s (comes to rest)
   • Time (t) = 5 s

2. Use the formula:

   • a = (v - u) ÷ t
   • a = (0 - 25) ÷ 5
   • a = -25 ÷ 5 = -5 m/s²

3. Interpret: The negative sign indicates deceleration. The car is slowing down at 5 m/s².

Answer: The car’s acceleration is -5 m/s² (deceleration of 5 m/s²).

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Distance-Time Graphs: Visualizing Motion

Distance-time graphs show how the distance traveled by an object changes with time. Learning to read and draw these graphs is essential for IGCSE Physics.

Key Features of Distance-Time Graphs

Graph Feature	What It Means	Physics Interpretation
Steep gradient	Large distance covered quickly	High speed
Shallow gradient	Small distance covered slowly	Low speed
Horizontal line	No change in distance	Object is stationary
Straight line	Constant speed	Uniform motion
Curved line	Changing speed	Acceleration or deceleration

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How to Read Distance-Time Graphs

1. Stationary Object

Distance (m)
    |
    |───────────  (horizontal line)
    |
    └──────────────── Time (s)

Interpretation: The object is not moving. Distance remains constant.

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2. Constant Speed

Distance (m)
    |
    |        /
    |      /
    |    /        (straight line)
    |  /
    |/
    └──────────────── Time (s)

Interpretation: The object is moving at constant speed.
Speed = gradient of the line

Formula: Speed = Change in distance ÷ Change in time

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3. Increasing Speed (Acceleration)

Distance (m)
    |
    |          /
    |        /
    |      /        (curved line getting steeper)
    |    /
    |  /
    |/
    └──────────────── Time (s)

Interpretation: The object is accelerating. The gradient is increasing, meaning speed is increasing.

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4. Decreasing Speed (Deceleration)

Distance (m)
    |
    |  \
    |    \
    |      \      (curved line getting less steep)
    |        \
    |          \
    └──────────────── Time (s)

Interpretation: The object is decelerating. The gradient is decreasing, meaning speed is decreasing.

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Worked Example 5: Reading a Distance-Time Graph

The graph shows a car’s journey. Calculate: a) The speed during the first 4 seconds b) The speed between 4 s and 8 s c) What happens between 8 s and 12 s?

Distance (m)
  80|
    |                  /
  60|                /
    |              /
  40|            /
    |          /
  20|        /
    |      /
   0|────┴────────────────── Time (s)
    0  2  4  6  8  10 12

Solution:

a) Speed during first 4 seconds:

• Distance at 0 s = 0 m
• Distance at 4 s = 40 m
• Speed = (40 - 0) ÷ (4 - 0) = 40 ÷ 4 = 10 m/s

b) Speed between 4 s and 8 s:

• Distance at 4 s = 40 m
• Distance at 8 s = 80 m
• Speed = (80 - 40) ÷ (8 - 4) = 40 ÷ 4 = 10 m/s

c) Between 8 s and 12 s:

• The line is horizontal (distance stays at 80 m)
• The car is stationary

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Examiner Tips for Distance-Time Graphs

1. Always check the axes: Make sure you know what’s on the x-axis (usually time) and y-axis (usually distance)

2. Gradient = Speed: The steeper the gradient, the faster the speed

3. Horizontal = Stationary: A horizontal line means the object is not moving

4. Curved = Changing speed: If the line is curved, speed is changing (accelerating or decelerating)

5. Use a ruler: When calculating gradient, draw a triangle and measure accurately

6. Units matter: Always include units in your answers (e.g., m/s, km/h)

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Speed-Time Graphs: Understanding Acceleration

Speed-time graphs (also called velocity-time graphs) show how an object’s speed changes over time. These graphs are crucial for understanding acceleration and calculating distance traveled.

Key Features of Speed-Time Graphs

Graph Feature	What It Means	Physics Interpretation
Steep gradient	Large change in speed quickly	High acceleration
Shallow gradient	Small change in speed slowly	Low acceleration
Horizontal line	No change in speed	Constant speed (zero acceleration)
Straight line	Constant acceleration	Uniform acceleration
Area under graph	Distance traveled	Total distance covered

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How to Read Speed-Time Graphs

1. Constant Speed

Speed (m/s)
    |
 20 |───────────  (horizontal line)
    |
    └──────────────── Time (s)

Interpretation: Object is moving at constant speed (20 m/s).
Acceleration = 0 m/s²

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2. Constant Acceleration

Speed (m/s)
    |
 20 |        /
    |      /
 10 |    /        (straight line with positive gradient)
    |  /
   0|/
    └──────────────── Time (s)

Interpretation: Object is accelerating at a constant rate.
Acceleration = gradient of the line

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3. Constant Deceleration

Speed (m/s)
    |
 20 |\
    |  \
 10 |    \      (straight line with negative gradient)
    |      \
   0|        \
    └──────────────── Time (s)

Interpretation: Object is decelerating at a constant rate.
Acceleration = negative (deceleration)

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4. Increasing Acceleration

Speed (m/s)
    |
    |          /
    |        /
    |      /        (curved line getting steeper)
    |    /
    |  /
    |/
    └──────────────── Time (s)

Interpretation: Acceleration is increasing (non-uniform acceleration).

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Calculating Acceleration from Speed-Time Graphs

The gradient of a speed-time graph gives the acceleration.

Formula for Acceleration from Graph

Acceleration = Change in Speed ÷ Change in Time

Or:

a = (v₂ - v₁) ÷ (t₂ - t₁)

Where you choose two points on the line: (t₁, v₁) and (t₂, v₂)

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Worked Example 6: Finding Acceleration from Speed-Time Graph

Calculate the acceleration of the car from the speed-time graph shown below.

Speed (m/s)
  30|                    /
    |                  /
  20|                /
    |              /
  10|            /
    |          /
   0|─────────/────────────── Time (s)
    0  2  4  6  8

Solution:

1. Choose two points on the line:

   • Point 1: (0 s, 0 m/s) - starts at origin
   • Point 2: (8 s, 30 m/s)

2. Calculate acceleration:

   • a = (v₂ - v₁) ÷ (t₂ - t₁)
   • a = (30 - 0) ÷ (8 - 0)
   • a = 30 ÷ 8 = 3.75 m/s²

Answer: The car’s acceleration is 3.75 m/s².

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Calculating Distance from Speed-Time Graphs

The area under a speed-time graph represents the distance traveled.

Why Area = Distance?

Distance = Speed × Time

On a speed-time graph:

• Speed is on the y-axis
• Time is on the x-axis
• Area = Speed × Time = Distance

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Worked Example 7: Finding Distance from Speed-Time Graph

Calculate the total distance traveled from the speed-time graph.

Speed (m/s)
  30|
    |
  20|          ┌─────┐
    |        /│     │
  10|      /  │     │ \
    |    /    │     │  \
   0|───/─────┴─────┴───── Time (s)
    0  2  4   6   8

Solution:

Split the area into shapes:

1. Triangle (0 to 4 s):

   • Starts at (0 s, 0 m/s) and ends at (4 s, 20 m/s)
   • Area = ½ × base × height
   • Area = ½ × 4 s × 20 m/s = 40 m

2. Rectangle (4 to 6 s):

   • Constant speed at 20 m/s from 4 s to 6 s
   • Area = base × height
   • Area = 2 s × 20 m/s = 40 m

3. Triangle (6 to 8 s):

   • Starts at (6 s, 20 m/s) and ends at (8 s, 10 m/s)
   • Height = 20 - 10 = 10 m/s
   • Area = ½ × base × height
   • Area = ½ × 2 s × 10 m/s = 10 m

4. Total distance:

   • Total = 40 + 40 + 10 = 90 m

Answer: The total distance traveled is 90 m.

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Examiner Tips for Speed-Time Graphs

1. Gradient = Acceleration: Always calculate gradient for acceleration questions

2. Area = Distance: Remember that area under the graph gives distance traveled

3. Break into shapes: For complex graphs, split the area into rectangles, triangles, or trapeziums

4. Check units: Make sure your distance answer has units (m, km, etc.)

5. Negative area: If the graph goes below zero, the area represents distance in the opposite direction

6. Use graph paper: When drawing graphs, use graph paper for accuracy

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Freefall: Motion Under Gravity

Freefall occurs when an object falls under the influence of gravity only, with no air resistance or other forces acting on it.

Key Concepts of Freefall

Gravitational acceleration (g):

• On Earth, g ≈ 9.8 m/s² (often rounded to 10 m/s² for calculations)
• This is the acceleration due to gravity
• All objects in freefall accelerate at the same rate (ignoring air resistance)

Important points:

• Acceleration is constant (approximately 10 m/s² downward)
• Initial velocity is usually zero (dropped from rest)
• Speed increases by 10 m/s every second
• Direction is always downward (toward Earth)

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Freefall Equations

When an object is dropped from rest (u = 0) and falls under gravity:

Speed After Time t

v = gt

Where:

• v = final velocity (m/s)
• g = acceleration due to gravity (≈ 10 m/s²)
• t = time (s)

Distance Fallen After Time t

s = ½gt²

Where:

• s = distance fallen (m)
• g = acceleration due to gravity (≈ 10 m/s²)
• t = time (s)

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Worked Example 8: Freefall Speed

A stone is dropped from a cliff. Calculate its speed after 3 seconds. (Take g = 10 m/s²)

Solution:

1. Identify known values:

   • Initial velocity (u) = 0 m/s (dropped from rest)
   • Time (t) = 3 s
   • Acceleration (g) = 10 m/s²

2. Use the formula:

   • v = u + at
   • v = 0 + (10 × 3)
   • v = 30 m/s

Answer: The stone’s speed after 3 seconds is 30 m/s downward.

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Worked Example 9: Freefall Distance

A ball is dropped from rest. How far does it fall in 4 seconds? (Take g = 10 m/s²)

Solution:

1. Identify known values:

   • Initial velocity (u) = 0 m/s
   • Time (t) = 4 s
   • Acceleration (g) = 10 m/s²

2. Use the formula:

   • s = ½gt²
   • s = ½ × 10 × 4²
   • s = ½ × 10 × 16
   • s = 5 × 16 = 80 m

Answer: The ball falls 80 m in 4 seconds.

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Common Student Misconceptions and Errors

Misconception 1: Heavier Objects Fall Faster

❌ Wrong: “A heavier object falls faster than a lighter object”

✅ Correct: In the absence of air resistance, all objects fall at the same rate regardless of mass. This was demonstrated by Galileo’s experiments.

Why students get confused: In everyday life, we see a feather fall slower than a stone due to air resistance, not gravity.

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Misconception 2: Speed and Velocity Are the Same

❌ Wrong: “Speed and velocity mean the same thing”

✅ Correct: Speed is a scalar (no direction), velocity is a vector (has direction). A car can have the same speed but different velocities if moving in different directions.

Common exam error: Students write “speed is 50 m/s north” when they should say “velocity is 50 m/s north”

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Misconception 3: Constant Speed Means No Acceleration

❌ Wrong: “If speed is constant, acceleration is zero”

✅ Correct: This is true only if direction is also constant. An object moving in a circle at constant speed is still accelerating because its direction is changing.

Examiner tip: Always check if direction is changing!

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Misconception 4: Negative Acceleration Always Means Slowing Down

❌ Wrong: “Negative acceleration always means the object is slowing down”

✅ Correct: Negative acceleration means acceleration in the negative direction. If an object is moving backward (negative velocity) and has negative acceleration, it’s actually speeding up backward.

Example: A car reversing and accelerating backward has negative velocity and negative acceleration, so it’s speeding up.

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Common Exam Errors to Avoid

Error 1: Forgetting Units

❌ Wrong: “The speed is 50”
✅ Correct: “The speed is 50 m/s”

Examiner tip: Always include units in final answers. Units are worth marks!

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Error 2: Confusing Distance and Displacement

❌ Wrong: Using total path length for velocity calculations
✅ Correct: Use straight-line distance (displacement) for velocity

Example: If you walk 100 m east, then 50 m west, your displacement is 50 m east, not 150 m.

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Error 3: Misreading Graph Scales

❌ Wrong: Reading graph values without checking the scale
✅ Correct: Always check the scale on both axes before reading values

Example: Each square might represent 5 m/s, not 1 m/s.

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Error 4: Incorrect Gradient Calculation

❌ Wrong: Using wrong points or not drawing a proper triangle
✅ Correct: Choose two clear points on the line and draw a triangle to measure gradient accurately

Examiner tip: Use a ruler and choose points that are easy to read from the graph.

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Error 5: Wrong Formula Application

❌ Wrong: Using distance ÷ time for acceleration
✅ Correct: Acceleration = (v - u) ÷ t

Common mistake: Students confuse speed formula with acceleration formula.

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IGCSE Physics Practice Questions: Motion

Test your understanding with these exam-style questions:

Question 1: Speed Calculation

A train travels 360 km in 3 hours. Calculate its average speed in: a) km/h b) m/s

Solution:

a) Average speed in km/h:

• Speed = Distance ÷ Time
• Speed = 360 km ÷ 3 h = 120 km/h

b) Average speed in m/s:

• Convert: 120 km/h = 120 ÷ 3.6 = 33.3 m/s (1 d.p.)

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Question 2: Acceleration from Velocity Change

A cyclist increases their speed from 5 m/s to 15 m/s in 4 seconds. Calculate the acceleration.

Solution:

1. Identify known values:

   • Initial velocity (u) = 5 m/s
   • Final velocity (v) = 15 m/s
   • Time (t) = 4 s

2. Use the formula:

   • a = (v - u) ÷ t
   • a = (15 - 5) ÷ 4
   • a = 10 ÷ 4 = 2.5 m/s²

Answer: The cyclist’s acceleration is 2.5 m/s².

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Question 3: Distance-Time Graph Analysis

The distance-time graph shows a runner’s journey. Describe the motion: a) Between 0 and 5 seconds b) Between 5 and 10 seconds c) Between 10 and 15 seconds

Distance (m)
  50|
    |                  /──────
  30|                /
    |              /
  10|            /
    |          /
   0|────────┴─────────────── Time (s)
    0  2  4  6  8 10 12 14

Solution:

a) Between 0 and 5 seconds:

• Steep straight line
• Running at constant speed

b) Between 5 and 10 seconds:

• Horizontal line (distance constant at 30 m)
• Stationary (not moving)

c) Between 10 and 15 seconds:

• Straight line with positive gradient
• Running at constant speed again (but may be different speed)

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Question 4: Speed-Time Graph - Distance Calculation

Calculate the total distance traveled from the speed-time graph below.

Speed (m/s)
  20|        ┌─────┐
    |      /│     │\
  10|    /  │     │ \
    |  /    │     │  \
   0|┴──────┴─────┴─────┴──── Time (s)
    0  2    4     8   10

Solution:

Split into shapes:

1. Triangle (0-2 s):

   • Area = ½ × 2 × 10 = 10 m

2. Rectangle (2-4 s):

   • Area = 2 × 10 = 20 m

3. Rectangle (4-8 s):

   • Area = 4 × 20 = 80 m

4. Triangle (8-10 s):

   • Area = ½ × 2 × 20 = 20 m

5. Total distance:

   • Total = 10 + 20 + 80 + 20 = 130 m

Answer: Total distance traveled is 130 m.

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Question 5: Freefall Problem

A stone is dropped from a height of 80 m. Calculate: a) The time taken to reach the ground b) The speed when it hits the ground (Take g = 10 m/s²)

Solution:

a) Time to reach ground:

• Using s = ½gt²
• 80 = ½ × 10 × t²
• 80 = 5t²
• t² = 16
• t = 4 s

b) Speed when hitting ground:

• Using v = gt
• v = 10 × 4 = 40 m/s

Answer:

• a) Time = 4 seconds
• b) Speed = 40 m/s

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Key Formulas Summary

Speed and Velocity

• Speed: Speed = Distance ÷ Time
• Velocity: Velocity = Displacement ÷ Time
• Average Speed: Average Speed = Total Distance ÷ Total Time

Acceleration

• Acceleration: a = (v - u) ÷ t
• Where: v = final velocity, u = initial velocity, t = time

Freefall

• Speed after time t: v = gt (when dropped from rest)
• Distance fallen: s = ½gt² (when dropped from rest)
• g ≈ 10 m/s² on Earth

Unit Conversions

• km/h to m/s: ÷ 3.6
• m/s to km/h: × 3.6

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Graph Interpretation Summary

Distance-Time Graphs

• Gradient = Speed
• Horizontal line = Stationary
• Straight line = Constant speed
• Curved line = Changing speed

Speed-Time Graphs

• Gradient = Acceleration
• Area under graph = Distance traveled
• Horizontal line = Constant speed (zero acceleration)

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Frequently Asked Questions About IGCSE Physics Motion

What is the difference between speed and velocity?

Speed is a scalar quantity (magnitude only) - it tells you how fast something is moving. Velocity is a vector quantity (magnitude and direction) - it tells you how fast AND in which direction something is moving. Speed = distance ÷ time, while velocity = displacement ÷ time.

How do I calculate acceleration from a speed-time graph?

The gradient (slope) of a speed-time graph gives the acceleration. Draw a triangle between two points on the line, then calculate: Acceleration = (change in speed) ÷ (change in time).

What does the area under a speed-time graph represent?

The area under a speed-time graph represents the distance traveled. To calculate it, split the area into rectangles, triangles, or trapeziums, calculate each area, then add them together.

Why do all objects fall at the same rate in freefall?

In the absence of air resistance, all objects accelerate at the same rate (≈ 10 m/s²) due to gravity, regardless of their mass. This is because the force of gravity is proportional to mass, and acceleration = force ÷ mass, so mass cancels out.

How do I convert between km/h and m/s?

• km/h to m/s: Divide by 3.6 (or multiply by 5/18)
• m/s to km/h: Multiply by 3.6 (or divide by 5/18)

Example: 108 km/h = 108 ÷ 3.6 = 30 m/s

What is the difference between distance and displacement?

Distance is the total path length traveled (scalar, always positive). Displacement is the straight-line distance from start to finish with direction (vector, can be positive or negative).

Example: If you walk 10 m east, then 5 m west:

• Distance = 15 m
• Displacement = 5 m east

How do I read a distance-time graph?

• Gradient = Speed (steeper = faster)
• Horizontal line = Stationary (not moving)
• Straight line = Constant speed
• Curved line = Changing speed (accelerating or decelerating)

What is freefall acceleration on Earth?

On Earth, the acceleration due to gravity (g) is approximately 9.8 m/s², but in IGCSE exams it’s often rounded to 10 m/s² for simplicity.

Can acceleration be negative?

Yes! Negative acceleration means acceleration in the negative direction. If an object is moving forward and has negative acceleration, it’s decelerating (slowing down). If it’s moving backward with negative acceleration, it’s speeding up backward.

How do I avoid common mistakes in motion questions?

1. Always include units in your answers
2. Distinguish between distance (scalar) and displacement (vector)
3. Use the correct formula - don’t confuse speed with acceleration
4. Check graph scales carefully before reading values
5. When calculating gradient, draw a proper triangle and measure accurately
6. For area calculations, split complex shapes into rectangles and triangles

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Related IGCSE Physics Resources

Strengthen your IGCSE Physics preparation with these comprehensive guides:

• IGCSE Physics Physical Quantities and Measurement Techniques - Foundation concepts before studying motion
• IGCSE Physics Motion, Forces and Energy - Complete topic coverage with videos, slides, and quizzes
• IGCSE Physics Revision Notes and Syllabus - Complete syllabus overview and revision strategies
• IGCSE Past Papers Guide - Access free IGCSE Physics past papers and exam resources

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• Interactive whiteboard sessions for visual learning
• Graph interpretation practice with detailed feedback
• Progress tracking to identify and strengthen weak areas
• Flexible scheduling to fit your revision timetable

Book a free IGCSE Physics trial lesson and get personalized support to master motion, graphs, and achieve your target grade in Cambridge IGCSE Physics (0625).

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