Grade 5 (age 10-11)

Motion of Objects

Speed tells you how far something travels in a set time, so we find it by dividing distance by time. Going farther in the same time, like a car outrunning a bike, means a faster speed. Slide the speed to move the car, then watch the distance-time graph line climb more steeply.

What is speed?

Speed40 km/h

🚗 Meaning of Speed

①Speed: distance moved per unit time

②Going farther in the same time = faster

③Units: km/h (per hour), m/s (per second)

④The first to finish in a race has higher speed

How do we find speed?

Speed Formula

Speed = DistanceTime

100 m in 20 s → speed = 100 / 20 = 5 m/s

Calculation Example

300 km in 3 h → 3003 = 100 km/h

KTX ≈ 300 km/h, car ≈ 80 km/h

💡 Comparing Speeds

①Same distance: shorter time = faster

②Same time: longer distance = faster

③Different both? Calculate speed to compare

Distance-Time Graph

📊 Motion on a Graph

①X-axis: time, Y-axis: distance

②Straight line = constant speed

③Steeper line = faster

④Flat line = stopped!

Summary

Motion Core

Speed = DistanceTime

Check the units! km/h or m/s

🎯 Key Points

①Speed = distance / time

②Same distance, less time = faster

③Same time, more distance = faster

④Steeper graph line = faster

⑤Walk 4 km/h, bike 15 km/h, car 80 km/h

Examples and Unit Test

Example 1

A person runs 100 m in 20 seconds. What is their speed in m/s?

Speed = distance ÷ time.

100 m ÷ 20 s = 5 m/s.

▸ 5 m/s

Speed is distance divided by time. Always check the units (m/s or km/h).

Example 2

A car travels 300 km in 3 hours. What is its speed, and on a distance-time graph, what does a faster speed look like?

Speed = distance ÷ time = 300 km ÷ 3 h = 100 km/h.

On a distance-time graph, a faster speed makes the line steeper.

▸ 100 km/h / a steeper line

A steeper distance-time line means a faster speed; a flat line means stopped.

Unit-test style

Which statement about the motion of objects is correct?

①Speed is found as time ÷ distance

②For the same distance, a shorter time means a faster speed

③On a distance-time graph, a gentler line means faster

④The unit of speed is the kilogram

⑤A flat line (no change in distance) means moving fast

▸ ② For the same distance, a shorter time means a faster speed

Speed = distance ÷ time, so for the same distance a shorter time gives a higher speed.

Speed is distance ÷ time (①), a steeper line is faster (③), speed units are m/s or km/h (④), and a flat line means stopped (⑤).

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