Derive Law Of Conservation Of Momentum-Class 11 Physics Notes

According to Newton’s second law of motion, the net external force acting on a body or system is equal to the rate of change of its momentum.
i.e. F_ext=ΔP/Δt
F_ext = Net external force acting on the system

P = Momentum of the system

When F_ext=0, ΔPΔt=0
⇒ΔP = 0
⇒P = constant
Therefore momentum of the system will be conserved when no net external force acts on the system.