Speed: distance divided by time
How far in each second?
A toy car
A toy car goes a long way in a short time. Another goes a short way in a long time.
How could we put its speed in one number?
What this lesson covers
The idea
Speed is the distance covered by an object in unit time: Speed = Total distance covered / Total time taken.
A toy car
A toy car goes a long way in a short time. Another goes a short way in a long time.
How could we put its speed in one number?
- Divide the distance by the time
- Add the distance and the time
- Multiply the distance by the time
Distance and time
Slide the distance and the time. Find a way to make 4 m/s.
Distance in one unit of time
40 m in 10 s means 4 m in each second. 80 m in 20 s is also 4 m in each second. Speed is the distance covered in a unit of time.
Speed is the distance covered by an object in unit time: Speed = Total distance covered ÷ Total time taken.
Notes
Speed is the distance covered by an object in unit time: Speed = Total distance covered ÷ Total time taken.
Check yourself
A cyclist covers 60 m in 20 s. What is the speed?
Answer: 3 m/s
60 m ÷ 20 s = 3 m/s.
Speed is the distance covered in …
A runner covers 100 m in 20 s. What is the speed?
Answer: 5 m/s
100 m ÷ 20 s = 5 m/s.
Which formula is correct?
- the whole day. Speed is about a unit of time, such as one second or one hour.
- no time. If no time passed, no distance could be covered.
- unit time — correct. Yes!
- Speed = Total distance covered ÷ Total time taken — correct. Yes!
- Speed = Total time taken ÷ Total distance covered. That is upside down. Speed is the distance divided by the time.
- Speed = Total distance covered × Total time taken. Speed is found by dividing, not multiplying.