Hey kids! Today, we’re going to learn about the fun topic of “speed” in math and some tips to solve related problems easily. Here are three simple points and formulas to help you understand and apply the concept of speed.
What is Speed?
Speed is really simple—it’s just how far you can travel in a certain amount of time. For example, if someone walks 5 kilometers per hour, it means they can walk 5 kilometers in one hour.
Three Key Points to Solve Speed Problems
- Use the Right Formula
- Unit Conversion
- Understand the Problem
1. Use the Right Formula
Speed problems often ask questions like:
- How far can a person walk in 2 hours if they walk at 5 kilometers per hour?
- If someone walked 10 kilometers in 2 hours, what was their speed?
- If someone needs to walk 10 kilometers and their speed is 5 kilometers per hour, how long will it take?
Here are the formulas you’ll need:
- Distance = Speed × Time
- Speed = Distance ÷ Time
- Time = Distance ÷ Speed
Example:
If Tim walks at 4 kilometers per hour for 3 hours, how far does he walk? Use the formula: Distance = Speed × Time = 4 km/h × 3 hours = 12 kilometers.
2. Unit Conversion
In speed problems, converting units is very important. For example:
- 1 kilometer = 1000 meters
- 1 hour = 60 minutes = 3600 seconds
- Speed per minute (m/min) = Speed per second (m/s) × 60
- Speed per hour (km/h) = Speed per minute (m/min) × 60 = Speed per second (m/s) × 3600
Example:
If a car’s speed is 10 meters per second, what is its speed in kilometers per hour? Calculate: Speed = 10 m/s × 3600 s/h = 36000 m/h = 36 km/h.
3. Understand the Problem
Some speed problems can be a bit tricky and need you to understand the question well. For example: Tim starts walking from home at 4 kilometers per hour. Five minutes later, Sam starts chasing Tim at 6 kilometers per hour. How long will it take Sam to catch up with Tim?
For such problems, drawing a picture can help understand the situation, and then you can work step by step to find the solution.
Example:
If Tim and Sam start at different times but we know their speeds, we can draw a chart to see where they are at different times and calculate how long it takes Sam to catch up to Tim.
Summary
Speed problems are not difficult. By remembering the formulas, converting units, and understanding the questions, you can easily solve them. Keep going, kids! Math is fun!
