posted by Judith .
A lightyear is a unit of length equal to the distance that light travels in 1 year. What is 1
lightyear expressed in units of meters? The speed of light is 3.00 × 108 m/s.
The speed is 3.00E8 m/s so it will travel in 1 year how far?
There are 60 seconds in minute.
There are 60 minutes in 1 hour.
There are 24 hours in a day.
There are 365 days in a year.
Put all of that together. You know the factor is set up correctly if the unit you don't want to keep cancels and leaves the unit you want to keep. The first factor is
3.00E8 m/s x (60 sec/min). Note the sec cancel and leaves you with 3.00E8m/min. The next factor will convert to hours, the next to days, the next to years.