Important Equations and Quantities

**Table 8.1:** Units commonly used in Collisions and Explosions
Units
Quantity	Symbol	Unit	SI base units	Direction
velocity	${\overrightarrow {v}}$	--	${\frac {\mbox{m}}{\mbox{s}}}$ or $\ \ {\mbox{m}}\cdot {\mbox{s}}^{-1}$	yes
momentum	${\overrightarrow {p}}$	--	${\frac {{\mbox{kg}}\cdot {\mbox{m}}}{\mbox{s}}}$ or $\ \ {\mbox{kg}}\cdot {\mbox{m}}\cdot {\mbox{s}}^{-1}$	yes
energy	E	J	${\frac {{\mbox{kg}}\cdot {\mbox{m}}^{2}}{{\mbox{s}}^{2}}}$ or $\ \ {\mbox{kg}}\cdot {\mbox{m}}^{2}\cdot {\mbox{s}}^{-2}$	no

Momentum:

{\begin{matrix}{\overrightarrow {p}}=m{\overrightarrow {v}}\end{matrix}}

(8.13)

Kinetic energy:

{\begin{matrix}E_{k}={\frac {1}{2}}m{\overrightarrow {v}}^{2}\end{matrix}}

(8.14)