Question

A red kangaroo hops at an average speed of 20km per hour. How fast is this in meters per minute?

Answer 1

333.3 meters per minute

Explanation:

The best way to solve this problem is using dimensional anaysis. First, we write out our starting units, that being 20km/1hr. We have to keep in mind that we want to change the kilometers to meters and the hours to minutes.

`(20km)/(1hr)`

We know that there are 1000 meters in 1 kilometer. We add this to the dimensional analysis as 1000m/1km. We write it as this because we want the kilometers to cancel each other out. We only want the meters.

`= (20km)/(1hr) *(1000m)/(1km) ...`

We also know that 1 hour is 60 minutes. We add this to the analysis as well so that the hours cancel each other.

`= (20km)/(1hr) *(1000m)/(1km) * (1hr)/(60min)`

We now solve this expression. Since both the kilometers and the hours cancel out, we have meters per minute as our unit. All that's left are the numbers.

= (20*1000*1)/(1*1*60) m/min

= 333.3 meters per minute