🏃 What is Speed?
Speed tells us how fast something is moving. It measures how much distance an object covers in a certain amount of time. A cheetah running across the grass has a high speed, while a snail crawling along has a very low speed!
The Speed Formula
To find speed, we divide the distance traveled by the time it took:
🧮 Speed Formula:
\( \text{Speed} = \dfrac{\text{Distance}}{\text{Time}} \)
\( s = \dfrac{d}{t} \)
Speed is usually measured in meters per second (m/s) or kilometers per hour (km/h).
📝 Let's Try It:
If you ride your bike 100 meters in 20 seconds, your speed is:
\( \dfrac{100\ \text{m}}{20\ \text{s}} = 5\ \text{m/s} \)
That means you travel 5 meters every single second!
Think of it Like This
💡 The Race Idea:
Imagine two friends racing to the same tree. The one who gets there in less time was moving faster — they had a higher speed. Speed is all about covering distance quickly!
📝 Real-World Speeds:
- A person walking: about 1.4 m/s (5 km/h)
- A person running fast: about 8 m/s (29 km/h)
- A car on the highway: about 28 m/s (100 km/h)
- A jet airplane: about 250 m/s (900 km/h)
- Light: a super-speedy 300,000,000 m/s!
Speed vs. Velocity
Sometimes scientists use the word velocity. Velocity is just like speed, but it also tells you the direction you're moving!
- Speed: "I'm going 5 m/s." (just how fast)
- Velocity: "I'm going 5 m/s toward the north." (how fast AND which way)
📚 Quick Summary
🏃 Speed
How fast something moves — distance divided by time
🧮 Formula
Speed = Distance ÷ Time \( (s = \dfrac{d}{t}) \)
📐 Units
Measured in m/s or km/h
🧭 Velocity
Speed in a particular direction
➡️ Keep Exploring
📏 Distance
Learn about distance — how far an object actually travels.
⏱️ Time
Learn about time — the other ingredient in the speed formula.
🚀 Acceleration
Learn about acceleration — what happens when speed changes.