SI Unit Conversion Problem:

Question

If your front lawn is 23.0 feet wide and 20.0 feet long, and each square foot of lawn accumulates 1250 new snowflakes every minute, how much snow, in kilograms, accumulates on your lawn per hour? Assume an average snowflake has a mass of 1.70 mg

Answer 1

We can first calculate the area of the lawn in square feet and then use the given 1250 snowflakes/square foot relationship as a conversion factor to calculate the number of snowflakes falling on the the lawn in one minute.

Area = Length x Width

Area = (20.0 ft)(23.0 ft) = 460 ft²

460 ft² x (1250 snowflakes/1 ft²) = 575,000 snowflakes/min

From here we can calculate the number of snowflakes falling on the lawn in an hour and then calculate the total mass.

575,000 snowflakes/min x (60 min/1 hr) = 34500000 snowflakes

34500000 snowflakes x (1.70 mg/1 snowflake) x (1 g/1000 mg) x (1 kg/1000 g) = 58.7 kg (or 58.65 kg without significant figures)