on . Posted in Classical Mechanics

momentum 5Momentum, abbreviated as p, also called linear motion or translational momentum, is the measure of inertia for objects in motion.  It helps quantify how difficult it is to stop something.  Momentum has both magnitude and direction, making it a vector quantity.  The change in momentum is called impulse.

The law of conservation of momentum states that the total momentum of a closed system remains constant if no external forces act on it.  This means that in the absence of external forces, the total momentum of a system before an event must be equal to the total momentum after the event.  This principle is often applied in the analysis of collisions and explosions.

Momentum Types

  • Linear Momentum   -  This is the most common type of momentum and is associated with the motion of an object in a straight line.  It is defined as the product of an object's mass and its linear velocity.
  • Angular Momentum  -  This type of momentum is associated with the rotation or spinning of an object.  It depends on the object's moment of inertia and its angular velocity.
  • Impulse Momentum  -  Impulse is the change in momentum of an object.  It is the product of the force applied to an object and the time over which the force is applied.
  • Relativistic Momentum  -  In the context of special relativity, momentum is modified due to the relativistic effects at high velocities.


Momentum formula

\( p = m \; v   \)     (Momentum)

\( m =  p \;/\; v    \)

\( v = p \;/\; m    \)

Symbol English Metric
\( p \) = momentum \(lbm-ft\;/\;sec\)  \(kg-m\;/\;s\) 
\( m \) = mass \(lbm\) \(kg\)
\( v \) = velocity \(ft\;/\;sec\) \(m\;/\;s\)


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Tags: Motion Momentum Inertia