Understanding Distance and Speed

Lesson 2 of 6: Distance, Time and Speed

In this lesson:

• Measure distance using km and m
• Understand what speed means
• Read and use speed units (km/hr, m/sec)

What You Will Learn Today

By the end of this lesson:

1. Use correct units for distance (km, m)
2. Explain what speed means in everyday language
3. Use correct units for speed (km/hr, m/sec)
4. Understand what "/" means in speed units
5. Compare the speeds of different objects

How Far Is Your Home from School?

Think about distances you already know:

• Your home to school — close or far?
• Kampala city to the bus park
• A classroom from one wall to the other

Distance: Units and the Scale Rule

Distance is how far apart two places or objects are.

Metres or Kilometres? Real Examples

Metres (m) — short distances:

• Person's height ≈ 1.5 m
• Classroom length ≈ 8 m
• Football field ≈ 100 m

Kilometres (km) — long distances:

• Kampala to Entebbe ≈ 37 km
• Kampala to Jinja ≈ 80 km

Quick Check: Pick the Right Unit

Which unit would you use?

1. Distance from your desk to the chalkboard
2. Distance from Kampala to Mbarara
3. Length of a football field
4. Distance a matatu travels in a day

Decide each one, then advance.

Quick Check: Units — All Four Answers

1. Desk to chalkboard → metres (short, can see across)
2. Kampala to Mbarara → kilometres (long journey)
3. Football field → metres (100 m, walkable)
4. Matatu's daily distance → kilometres (many km)

Rule: Walk it in a minute? → metres. Real journey? → kilometres.

Converting km to m: Worked Examples

Going km → m (smaller unit) → multiply × 1,000

Converting m to km: Worked Examples

Going m → km (larger unit) → divide ÷ 1,000

Practice: Four Distance Conversion Problems

Solve these on your own:

1. 4 km = ___ m
2. 6,000 m = ___ km
3. 1.5 km = ___ m
4. 250 m = ___ km

Try all four, then advance.

Practice: Check Your Conversion Answers

1. 4 × 1,000 = 4,000 m
2. 6,000 ÷ 1,000 = 6 km
3. 1.5 × 1,000 = 1,500 m
4. 250 ÷ 1,000 = 0.25 km

Going smaller → × 1,000 · Going larger → ÷ 1,000

Speed: Distance Covered in a Given Time

We know distance. We know time.

Speed connects them: it tells us how much distance is covered in a given amount of time.

A person who walks 5 km in 1 hour has a speed of 5 km per hour.

Speed Units: What the "/" Means

Speed is measured in two main units:

The "/" means "per" or "in every".

Quick Check: Explain What km/hr Means

In your own words:

"A boda-boda travels at 40 km/hr."

What does 40 km/hr mean? Use "in every" or "per".

Think before advancing...

Quick Check: What 40 km/hr Really Means

40 km/hr: the boda-boda covers 40 km in every hour.

• 1 hour of travel → 40 km covered
• 2 hours of travel → 80 km covered

The number = how many km · "/hr" = per hour

Real Speed Examples from Uganda

Comparing Speeds: Slowest to Fastest

Which is fastest? Which is slowest?

Walking (5) → Cycling (15) → Boda-boda (40) → Car (80)

All in km/hr — so the largest number is fastest.

Quick Check: Can You Compare These Speeds?

Which is faster?

Option A: 20 km/hr
Option B: 50 km/hr

And: could you compare 4 km/hr with 2 m/sec directly?

Think through both before advancing.

Quick Check: Speed Comparisons — Answers

Option B (50 km/hr) is faster — same units, larger number wins.

4 km/hr vs 2 m/sec: cannot compare directly — different units need converting first.

Always check units before comparing.

Quick Assessment: Answer All Six Questions

1. What two units measure distance?
2. Convert 4 km to metres.
3. What does "speed" mean?
4. What does "/" mean in km/hr?
5. What two units measure speed?
6. Which is faster: 4 km/hr or 12 km/hr?

Answer all six, then advance.

Quick Assessment: All Six Answers

1. km and m
2. 4 × 1,000 = 4,000 m
3. Distance covered in a certain time
4. "/" means "per"
5. km/hr and m/sec
6. 12 km/hr — larger number, same units

Key Takeaways from Today's Lesson

✓ m = short · km = long; 1 km = 1,000 m

✓ Speed = distance in a given time

✓ "/" = per · km/hr = km per hour · m/sec = m per second

1 km = 1,000 m, not 100

Compare speeds only with matching units

Always write the unit

Next Lesson: The Speed Formula

In Lesson 3, we will discover:

• Calculate speed when you know distance and time
• Find distance when you know speed and time
• Find time when you know speed and distance

Homework: Complete conversions, unit-matching exercises, and the boda-boda question in your exercise book.