seegongsik
Saved words
Grade 6 (age 11-12)

Speed

Speed

Speed tells you how fast something moves, and you find it by dividing the distance traveled by the time it takes. A car that goes 100 kilometers in 2 hours covers 50 kilometers each hour, so we say its speed is 50 kilometers per hour. You meet speed all around you, from a car dashboard to a running record. Here you can change the distance and time to see how the speed shifts, and compare how fast two objects move side by side.

What is Speed?
🚗 Speed in Numbers
①Going farther in the same time is faster
②Same distance in shorter time is faster
③Speed = Distance ÷ Time
Calculating Speed
120 km
2 h
Comparing Speeds
60 km/h
80 km/h
Summary
Speed Formula
Speed = DistanceTime
Units: km/h, m/s, etc.
Distance
Distance = Speed × Time
Distance from speed and time
Time
Time = DistanceSpeed
Time from distance and speed
🎯 Key Points
①Speed = Distance ÷ Time
②Units: km/h, m/s, m/min
③Higher speed → faster
④Distance = Speed × Time; Time = Distance ÷ Speed
⑤Conversion: 1 km/h = 1000/3600 m/s
Examples & Unit Review
Example 1
A car travels 240 km in 4 hours. What is its speed?
1
Speed = distance ÷ time = 240 ÷ 4.
2
240 ÷ 4 = 60, so 60 km/h.
▸ 60 km/h
Speed is the distance covered in one hour (or one second).
Example 2
Driving at 80 km/h for 3 hours, how far do you go?
1
Distance = speed × time = 80 × 3.
2
80 × 3 = 240 km.
▸ 240 km
If you know two of distance, speed, and time, you can find the third.
Unit Review
How long does it take to travel 150 km at 50 km/h?
①3 hours
②2 hours
③5 hours
④100 hours
▸ ① 3 hours
1
Time = distance ÷ speed = 150 ÷ 50.
2
150 ÷ 50 = 3, so 3 hours.
← Previous
Percentage
Next →
Variables & Expressions