# Unit conversion: Time and distance

The quiz for this lesson is coming soon.

## Unit conversion: Time and distance

​On a good day, Lena can get her scooter to make 36 kilometers per hour. How many meters per second is that? These types of questions are often raised in mathematics where you need to convert between units. Let's take it one step at a time and start with kilometers. Kilo means 1,000.

So, 36 kilometers is 36,000 meters. Next, we turn hours into seconds. There are 60 minutes in one hour and 60 seconds in a minute. Sixty times 60 is 3,600. Six times six is 36 and two zeros to carry.

So now we have 36,000 meters and 3,600 seconds. But what do we do with them? We need meters per second. Look at the units. It says meters divided by seconds.

So, we take our 36000 meters and divide by 3600 seconds. Simplify by 100 in the numerator and denominator. There are 10 36s in one 360. Therefore, the scooter is moving at 10 meters per second. Did we calculate it correctly?

Is it a reasonable answer? Imagine a scooter passes you on the street, one 1000, two 1000, three 1000. Yes, 10 meters is about as far as she gets every second. One meter or 100 meters for an answer would not have been reasonable and we would have known we calculated it wrong. If you're converting many numbers between the same units, you don't need to do this long calculation each time.

Just calculate how many meters per second there are in one kilometer per hour. 1000 meters divided by 3600 seconds is approximately 0.278. Now you can take any speed expressed as kilometers per hour and convert it to meters per second by multiplying it by 0.278. Take a speed and kilometers per hour. Say 10, multiply it by 0.278, and you' will get to the answer in meters per second.

Increase the speed by 50% to 15 kilometers per hour, multiply it by 0.278, and note the speed increases by 50% in meters per second as well. Test it with 36 kilometers per hour as well where you already know the answer, 36X0.278. Yes, it's 10 here as well.