APPENDIX A

UNITS OF MEASUREMENT

It is important to quote scientific quantities in the correct units. Here are some of the more common units of measurement that you might use. Equations that can be used to calculate these variables are presented in Appendix D.

Variable

Unit name

Unit abbreviation

Distance

millimetre (millimeter in US)

mm

metre (meter)

m

kilometre (kilometer)

km

Speed

metres per second

m·s-1

Velocity

metres per second in a given direction

m·s-1 (a direction should be specified)

Acceleration

metres per second per second

m·s-2

Mass

kilogram

kg

Force

newton

N

Impulse

newton-second

N·s

Linear momentum

kilogram-metres per second

kg·m·s-1

Angular momentum

kilogram-metres squared per second

kg·m2·s-1

Moment of inertia

kilogram-metres squared

kg·m2

Torque

newton-metre

N·m

Work

joule

J

Power

watt

W

Energy

joule

J