kilometers per second

USAGE SUMMARY

The phrase "kilometers per second" is correct and usable in written English.
It can be used when discussing speed or velocity, particularly in scientific or technical contexts. Example: "The spacecraft travels at a speed of 30 kilometers per second, allowing it to reach distant planets in a shorter time."

✓ Grammatically correct

Academia

News & Media

Science

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

Generally, that velocity is some hundreds of kilometers per second.

Cornell University

So if velocity is in kilometers per second, then we should put our distance in kilometers.

The New York Times

We decided to convert kilometers per second to the more familiar units of miles per hour.

University of California, Berkeley

Short version: Earth's average orbital speed is about 30 kilometers per second.

Cornell University

As you read this, the universe expands at about 70 kilometers per second per megaparsec.

Cornell University

Also, a typical speed for meteorites is around 30 kilometers per second.

Cornell University

Here are the answers he was looking for: 1. Voyager 1 is moving at 17 kilometers per second.

The New York Times

In addition, the solar system is moving at about 20 kilometers per second with respect to the nearby stars.

Harvard University

1,000 kilometers per second, circling the planet in just five minutes". Since when was 1,000 km/sec 'ultrarelativistic'?

Massachusetts Institute of Technology

The low value for the Hubble constant means an expansion rate of 50 kilometers per second per megaparsec.

The New York Times

Genzel's team measured a velocity of 5,000 kilometers per second — 170 times faster than the Earth orbits the sun.

University of California, Berkeley

Expert writing Tips

Best practice

When writing for a general audience, consider providing a conversion to a more familiar unit of speed, such as miles per hour, alongside "kilometers per second" to enhance comprehension.

Common error

Avoid mixing "kilometers per second" with other units of measurement within the same context without proper conversion. For example, don't compare "kilometers per second" directly with distances measured in miles without converting either value.

Linguistic Context

The phrase "kilometers per second" functions as a unit of measurement, specifically quantifying speed or velocity. Ludwig confirms its correct usage in diverse contexts, similar to the examples shown. It describes how far something travels in a single second, expressed in kilometers.

Expression frequency: Very common

Frequent in

Academia

33%

News & Media

33%

Science

34%

Less common in

Ludwig's WRAP-UP

The phrase "kilometers per second" is a common and grammatically correct unit of measurement used to express speed or velocity, as validated by Ludwig. It is prevalent in academic, scientific, and news contexts, indicating a neutral to formal register. To enhance understanding for general audiences, it's beneficial to provide conversions to more familiar units. Ludwig's analysis of various sources highlights the importance of consistent unit usage to avoid confusion.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

km/s

This is a shorter, abbreviated form of "kilometers per second".

kilometers per second (km/s)

This includes the abbreviation after the full phrase.

speed in kilometers per second

This rephrases the sentence to emphasize the aspect of speed.

velocity in km/s

This uses 'velocity' instead of 'speed' and the abbreviation.

rate of kilometers per second

This uses the term 'rate' rather than 'speed' or 'velocity'.

velocity measured in kilometers per second

This specifies the method of measurement.

speed of X km/s

Expresses speed with a specific numerical value.

distance per unit of time

This is a more abstract description of speed, not specific to kilometers per second.

meters per second

Uses a different metric measurement unit.

miles per hour

Converts the speed to imperial units.

FAQs

How do I convert "kilometers per second" to miles per hour?

To convert "kilometers per second" to miles per hour, multiply the value in "kilometers per second" by 2236.94. This conversion helps to provide a more familiar understanding of the speed in a different unit.

When is it appropriate to use the abbreviation "km/s" instead of "kilometers per second"?

Use "km/s" in technical writing, scientific papers, or when space is limited. In general prose, especially for a non-technical audience, it's better to use "kilometers per second" for clarity. You could also use "speed in kilometers per second" or "velocity in km/s" to emphasize the measure.

What is a practical way to understand how fast something moving at "kilometers per second" is?

Compare it to everyday speeds. For example, Earth's orbital speed is about 30 "kilometers per second". Compare that to the speed of a car on a highway or a commercial airplane. For astronomical scales, you can use the "speed of light" for reference.

Is "kilometers per second" a measure of speed or velocity?

"Kilometers per second" is a measure of both speed and velocity. Speed refers to how fast an object is moving, while velocity specifies both speed and direction. Therefore, "kilometers per second" can quantify either, depending on the context. Alternative terms for expressing speeds include "rate of kilometers per second" or "velocity measured in kilometers per second".