Question

If a car is travelling at 21.8 kilometers per hour, how fast is that in millimeters per second?

Answer 1

I found: `6xx10^3(mm)/s`

Explanation:

Consider that:
`21.8km=21.8xx1000m=21800m`
but `1m=1000mm` so:
`21800m=21800xx1000=2.18xx10^7mm`

`1h=60min=60xx60=3600sec`
So:
`21.8(km)/h=(2.18xx10^7)/(3600)=6xx10^3(mm)/s`

Answer 2

`6055.5"mm/s"`

Explanation:

We have `21.8"km/hr"`

There are 1000m in 1 km so this gives us:

`21.8xx1000" ""m/hr"`

There are 60 min in 1 hour and 60 sec in 1 min so this gives us:

`(21.8xx1000)/(60xx60)" ""m/s"`

There are 1000mm in 1m so this gives us:

`(21.8xx1000xx1000)/(60xx60)" ""mm/s"`

`=6055.5" " "mm/s"`