Momentum

Momentum

2.5

Momentum

	Momentum : product of mass and velocity
	\(p=m\times v\)

	The principle of conservation of momentum
	The total momentum of a system is constant if there are no external forces acting on the system

Types of situations involving principle of conservation of momentum

Collision: Total momentum before collision is equal to the total momentum after the collision
Explosion: The total momentum before and after the explosion is zero

Elastic collision	Inelastic collision
Momentum, total energy and kinetic energy are all conserved.	Momentum and total energy conserved, but kinetic energy is not conserved.
\(m_1u_1+m_2u_2=m_1v_1+m_2v_2\)	\(m_1u_1+m_2u_2=(m_1+m_2)v\)

	Explosion
	Total momentum before and after explosion is zero. \(m_1v_1=-m_2v_2\)



	Example: rifle firing a bullet rocket launching