## Unuts, Conversion Factors and Constants

Distance is usually measured in metres, m, but can also be measured in centimetres, cm, millimetres, mm, kilometres, km or miles.

1 mile=1.609 km (often approximated to 1.6) = 1609 metres (often approximated to 1600) = 160900 cm = 1609000 mm

Speed is usually measured in metres per second, m/s, or kilometres per hour, km/h, or miles per hour, mph.

1 m/s =3.6 km/h =2.25 mph (using 1 mile =1.6 km)

Time is usually measured in seconds but can also be measured in minutes, hours, days and years.

1 minute = 60 seconds

1 hour = 60 minutes = 3600 seconds

1 day = 24 hours = 86400 seconds

1 year = 365 days = 31536000 seconds

Area is usually measured in square metres, m 2 , but can also be measured in square millimetres, mm 2 , square centimetres, cm 2 , square kilometres, km 2 , or square miles.

1 square mile = 2.56 km 2 = 2560000 m 2 =25600000000 cm 2 =2560000000000 mm 2 (using 1 mile = 1.6 km)

Volume is usually measured in cubic metres, m 3 , but can also be measured in cubic millimetres, mm 3 , cubic centimetres, cm 3 , cubic kilometres, km 3 , or cubic miles.

1 cubic mile = 4.096 km 3 = 4096000000 m 3 =256000000000000 cm 3 =256000000000000000 mm 3

(using 1 mile =1.6 km)

It is important that areas transform as, for example, 1m 2 =(100cm) 2 =10000 cm 2 and 1m 3 =(100cm) 3 =1000000 cm 3