Speed Unit Conversion
Speed is measured as the distance travelled per unit of time. For example, if a car travels at 40 km/h, it means that it travels 40 km every hour (40 km in one hour, 80 km in two hours, 120 km in three hours, etc.). A commonly used unit in the United States is mph (miles per hour). Since speed is expressed as a combination of two units (distance divided by time), when converting between different units of speed, we need to pay attention to both units — distance and time — and determine how to convert each of them.
If we are moving at 2 m/s, it means that every second we travel 2 metres. How many metres will we travel in one hour? One hour has 3600 seconds.
In one hour, we will travel 7200 m. And how many kilometres will we travel in one hour? We know that 1 km is equal to 1000 m.
If a car is moving at 90 km/h, how many metres per second does it travel? In this case, we have to multiply 90 by 1000 to convert kilometres to metres (90 km = 90000 m). At the same time, we have to divide by 3600 because one hour has 3600 seconds:
So the car is travelling at 25 m/s. But what is its speed in km/min? As we know, one hour has 60 minutes. This means that in one minute it travels:
