Question

The speedometer is marked in both \(\mathrm{km} / \mathrm{h}\) and \(\mathrm{mi} / \mathrm{h}\), or mph. What is the meaning of each abbreviation?

Short answer

km/h means kilometers per hour; mph means miles per hour.

Step-by-step solution

- Understand the abbreviation \(\text{km/h}\)

The abbreviation \(\text{km/h}\) stands for kilometers per hour. It is a unit of speed that tells how many kilometers are traveled in one hour.

- Understand the abbreviation \( \text{mph} \)

The abbreviation \( \text{mph} \) stands for miles per hour. It is a unit of speed that tells how many miles are traveled in one hour.

- Compare and contrast

Both \( \text{km/h} \) and \( \text{mph} \) measure speed but use different units of distance: kilometers for \( \text{km/h} \) and miles for \( \text{mph} \).

Key concepts

kilometers per hour

Kilometers per hour (km/h) is a common unit of speed measurement used around the world. It indicates the number of kilometers traveled in one hour. This measurement is primarily used in countries that follow the metric system, such as most European countries and many others across Asia and Africa. If you see a speed limit sign showing 50 km/h, it means you should not exceed a speed that would cover 50 kilometers in an hour.

Understanding and visualizing this can help in both comprehending speed limits and converting between various speed units when needed, such as when traveling internationally.

miles per hour

Miles per hour (mph) is another unit of speed measurement that's primarily used in countries like the United States and the United Kingdom. It indicates the number of miles traveled in one hour. To illustrate, if a car's speedometer reads 60 mph, it means the car is traveling at a speed that would cover 60 miles in one hour.

Knowing how to interpret mph is crucial for driving legally and safely in countries where this unit is standard. This understanding aids in grasping road signs, speed limits, and navigating via customary speed units efficiently.

speed conversion

Converting speeds between kilometers per hour and miles per hour can be very useful, especially if you are traveling or working with different measurement systems. The conversion factor between km/h and mph is approximately 1.609. Therefore, to convert from km/h to mph, you can divide the speed by 1.609.
For example:
\[ \text{Speed in mph} = \frac{\text{Speed in km/h}}{1.609} \]
Conversely, to convert from mph to km/h, multiply the speed by 1.609.
\[ \text{Speed in km/h} = \text{Speed in mph} \times 1.609 \]
This ability to convert is helpful when reading international speed signs, comparing speeds, and understanding different speed readings on vehicles or instruments marked in either units.
Mastering speed conversion ensures you can adapt to different driving environments and requirements seamlessly.