Speed

Question 1

What is speed?
A: Speed is the rate at which an object covers distance, and how fast it moves. It is a scalar quantity, meaning it has magnitude but no direction. The SI unit of speed is meters per second (m/s).

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Q: What are the formulas for speed, distance, and time?
Speed = Distance ÷ Time
Time = Distance ÷ Speed
Distance = Speed × Time

Flashcard 22
Q: What is average speed?
A: The term average speed is used when the speed of an object during a journey is not constant. Constant means not changing. So, average speed is used when the speed of the object might be changing during the journey.

Flashcard 23
Q: How is speed measured in different cases?
A:

The speed of ships is often measured in knots.
The speed of airplanes is often measured in Mach.
Some countries use kilometers per hour (km/h), and others use miles per hour (mph).
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Q: What is the highest possible speed?
A: The highest possible speed, since the 1930s, is thought to be the speed of light, which is 1,000,000,000 km/h.

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Q: How was the speed of light determined?
A: The speed of light was predicted by calculations made by Albert Einstein and confirmed by other scientists doing experiments.

Deck 6: Science and Measurement
Flashcard 26
Q: Why do scientists use standard scientific units?
A: Scientists use standard scientific units to avoid confusion and ensure consistency in communication.

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Q: What are the standard units for distance and time?
A:
The metre is the standard scientific unit of distance, symbol: m, where 1 m = 100 cm.
The second is the standard scientific unit of time; there are 60 seconds in 1 minute.

Flashcard 28
Q: What does “per” mean in speed measurements?
A: “Per” means “in each,” so “metres per second” refers to the number of metres travelled in each second.

Flashcard 29
Q: How does science advance?
A: Science advances through collaboration and peer-review.