Summary of Important Quantities, Equations and Concepts

Table 6.1: Summary of the symbols and units of the quantities used in Momentum

Units
Quantity	Symbol	Unit	SI base units		Direction
Momentum	${\displaystyle {\overrightarrow {p}}}$	-	kg·m·s−1		yes
Mass	m	kg	kg		--
Velocity	${\displaystyle {\overrightarrow {u}}}$, ${\displaystyle {\overrightarrow {v}}}$	-	m·s−1		yes
Change in momentum	${\displaystyle \Delta {\overrightarrow {p}}}$	-	kg·m·s−1		yes
Force	${\displaystyle {\overrightarrow {F}}}$	N	kg·m·s−2		yes
Impulse	J	N·s	kg·m·s−1		yes

Momentum: The momentum of an object is defined as its mass multiplied by its velocity.

Momentum of a System: The total momentum of a system is the sum of the momenta of each of the objects in the system.

Principle of Conservation of Linear Momentum:: `The total linear momentum of an isolated system is constant' or `In an isolated system the total momentum before a collision (or explosion) is equal to the total momentum after the collision (or explosion)'.

Law of Momentum:: The applied resultant force acting on an object is equal to the rate of change of the object's momentum and this force is in the direction of the change in momentum.