KS3 Physics · Motion

MISSION:
MEDIC-DRONE

A severe storm has cut off a remote island medical clinic. You are the Flight Controller. You must program a delivery drone to transport life-saving medicine. If your calculations are wrong — the drone crashes.

Y9 · Mixed Ability Distance Learning 50 Minutes 4 Phases

Mission Objectives

◈ Recall the difference between scalar and vector quantities
◈ Calculate speed, distance and time using v = s ÷ t
◈ Interpret Distance-Time graphs to describe a journey
◈ Interpret Velocity-Time graphs and calculate acceleration

Pre-Flight Check

UNLOCK THE DRONE OS

The drone's operating system is encrypted. Unscramble these navigation terms to gain access.

SYSTEM LOCKED — Six key terms must be identified before the drone can be programmed. Write your answers before checking.

E E D P S

First letter: S

I T Y O C L E V

First letter: V

R A C E L A T I O N E C A

First letter: A

A R C L A S

First letter: S

R O T C E V

First letter: V

N A E E S D T I C

First letter: D

Phase 1 — The Flight Path

SCALAR vs VECTOR

The drone has two navigation modes. You need to understand the difference.

Scalar

Has magnitude (size) only. No direction needed.

Examples: speed, distance, mass, temperature

Vector

Has magnitude AND direction. Both are needed.

Examples: velocity, displacement, force, acceleration

The drone's data feed is showing mixed sensor readings. Sort each reading into the correct column. Click a reading to assign it — first click = Scalar, second click = Vector, third click = unassign.

15 m/s

15 m/s North

500 m

500 m East

20°C (battery temp)

50 N (wind force)

Click once → Scalar Click again → Vector Click again → unassign

The drone flies 500 m East, then 500 m North. Its total distance travelled is 1,000 m (scalar — just the path length). But its displacement — the straight-line distance back to the start — is different. Can you calculate it? (Hint: Pythagoras)

Phase 2 — Cruising Speed

THE SPEED EQUATION

Before you can programme the drone, you need this relationship locked in.

v = s ÷ t

v = speed (m/s) · s = distance (m) · t = time (s)

Cover s → speed × time
Cover v → distance ÷ time
Cover t → distance ÷ speed

Typical Speeds Reference

Object	m/s	km/h
🚶 Walking	≈ 1.5	≈ 5
🏃 Running	≈ 3	≈ 11
🚲 Cycling	≈ 6	≈ 22
🚗 Car (urban)	≈ 13	≈ 50
🚗 Car (motorway)	≈ 30	≈ 110
✈️ Aeroplane	≈ 250	≈ 900
🔊 Speed of Sound	330	≈ 1,200

The drone's cruising speed is set to 13 m/s — equivalent to a car in a city.

Phase 2 — Cruising Speed

CAN THE DRONE MAKE IT?

Your calculations determine whether the medicine reaches the clinic.

The situation: The clinic is 4,500 m away. The drone's battery lasts 6 minutes. The drone flies at 13 m/s. Does it arrive before the battery dies?

1

Convert battery life to seconds

6 minutes = ? seconds
2

Calculate time needed at 13 m/s

t = s ÷ v = 4,500 ÷ 13 = ?
3

Mission decision

Compare your answer with the battery life in seconds. Does the drone make it? By how many seconds?

Worked Solution

Step 1: 6 × 60 = 360 seconds

Step 2: t = 4,500 ÷ 13 = 346 seconds (2 d.p.)

Step 3: 346 s < 360 s ✅ — The drone makes it, with 14 seconds to spare.

Headwind scenario: A 3 m/s headwind reduces the drone's effective speed.

New speed = 13 − 3 = 10 m/s
Recalculate time needed: t = 4,500 ÷ 10 = ?
Does it make it now?
If not — what minimum speed does the drone need?
v = s ÷ t = 4,500 ÷ 360 = ?

Stretch Answers

t = 4,500 ÷ 10 = 450 s — battery lasts 360 s ❌ Drone doesn't make it.

Minimum speed: v = 4,500 ÷ 360 = 12.5 m/s

Write down what you know first: s = 4,500 m, v = 13 m/s, t = ?
Then pick the right rearrangement from the formula triangle.
Remember: always include the unit in your answer.

Phase 3 — The Flight Log

ANALYSE THE DATA

The drone's recorder transmitted this Distance-Time graph. The Rescue Council need a full report.

Analysis Questions

1
Between which two times was the drone stationary? How can you tell from the graph?
2

Calculate the drone's speed during Segment 1 (0–100 s).

Speed = change in distance ÷ change in time
3
Calculate the drone's speed during Segment 3 (150–300 s).
4
Suggest one realistic reason why the drone stopped mid-flight.

Worked Answers

1. Stationary from 100 s to 150 s — the line is horizontal (distance not changing).

2. Speed = 600 ÷ 100 = 6 m/s

3. Speed = 300 ÷ 150 = 2 m/s

4. Sensor recalibration, obstacle avoidance, GPS lock, battery check, etc.

The gradient of a D-T graph gives the speed. Which segment has the steeper gradient? What does a steeper gradient tell you about the motion?

Phase 3 — The Flight Log

SKETCH THE GRAPH

Now draw the Flight Log yourself. Use the data from the drone's journey.

Journey data to plot:

0–100 s: drone travels from 0 to 600 m
100–150 s: drone is stationary at 600 m
150–300 s: drone travels from 600 m to 900 m

How to draw it: Use a ruler. Plot each point first, then join them. Label your axes — x-axis is Time (s), y-axis is Distance (m). Label each segment of your graph.

Axis scales: x-axis: 0 to 300 s (every 50 s). y-axis: 0 to 900 m (every 100 m).

Phase 4 — Emergency Landing

ACCELERATION

The drone must slow down fast. Understand the equation before you tackle the landing.

a = (v − u) ÷ t

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

What does each symbol mean?

Symbol	Meaning	Unit
`a`	Acceleration	m/s²
`v`	Final velocity (end speed)	m/s
`u`	Initial velocity (start speed)	m/s
`t`	Time taken	s
`v − u`	Change in velocity	m/s

Deceleration is negative acceleration — the object is slowing down. You get a negative value when v is smaller than u. Just state the magnitude and say "deceleration".

Worked Example

A cyclist accelerates from 0 to 10 m/s in 5 seconds. Find the acceleration.

1
u = 0 m/s, v = 10 m/s, t = 5 s
2
v − u = 10 − 0 = 10 m/s
3
a = 10 ÷ 5 = 2 m/s²

A ball decelerates from 15 m/s to rest in 3 s. Calculate the deceleration. Why is your answer negative?

Phase 4 — Emergency Landing

DOES IT FIT THE LANDING PAD?

The clinic's landing pad is only 40 m long. Will the drone stop in time?

ALERT: Drone approaching at 20 m/s. Landing pad length: 40 m. Time to decelerate to stop: 5 seconds. Calculate whether the drone can land safely.

1

Calculate the deceleration

a = (v − u) ÷ t = (0 − 20) ÷ 5 = ?

u = 20 m/s (start speed) · v = 0 m/s (touchdown) · t = 5 s
2

Find the landing distance from the V-T graph

Area under a V-T graph = distance travelled. The shape is a triangle.

Area = ½ × base × height = ½ × 5 × 20 = ?
3

Mission critical decision

Landing pad = 40 m. Landing distance = your answer. Does the drone stop in time? What do you recommend?

Worked Solution

Step 1: a = (0 − 20) ÷ 5 = −20 ÷ 5 = −4 m/s² (deceleration of 4 m/s²)

Step 2: Distance = ½ × 5 × 20 = 50 m

Step 3: Pad = 40 m, but drone needs 50 m ❌ — The drone does not stop in time. Recommend reducing approach speed before final descent.

If the drone only has 3 seconds to stop, what deceleration is now required?

a = (0 − 20) ÷ 3 = ?

Stretch Answer

a = −20 ÷ 3 = −6.67 m/s² — a much greater deceleration. For a delivery drone this may cause it to tip or damage the cargo.

Mission Debrief

KEY CONCEPTS

Everything you needed to complete the mission — locked in for good.

⬡

Scalar vs Vector

Scalar = size only (speed, distance). Vector = size + direction (velocity, displacement). The drone needs both.

◈

Speed Equation

v = s ÷ t — always write your known values first. Rearrange using the triangle. Always include units.

◉

D-T Graphs

Gradient = speed. Flat line = stationary. Steeper gradient = faster. Downward slope = moving back.

△

Acceleration

a = (v − u) ÷ t — negative answer = deceleration (slowing down). State the magnitude and direction.

▣

V-T Graphs

Gradient = acceleration. Area under the graph = distance travelled. Break into triangles + rectangles.

🔗

Final Quiz

Complete the Final Quiz on the revision site to confirm your knowledge.
alexgray84.github.io →

QUICK ANSWERS REFERENCE

PHASE 2

Battery life = 360 s · Time needed = 346 s · ✅ Makes it by 14 s

Headwind: needs 450 s ❌ · Min speed = 12.5 m/s

PHASES 3 & 4

Seg 1 speed = 6 m/s · Seg 3 speed = 2 m/s · Stationary 100–150 s

Deceleration = 4 m/s² · Landing distance = 50 m ❌ (pad = 40 m)