The linear momentum of a system of rigid bodies will be conserved, if

Explanation:

Conservation of linear momentum:

If the net external force acting on a system of bodies is zero, then the momentum of the system remains constant.

Linear momentum is mathematically expressed as:

\(p=m\;\times\;v\)

p = linear momentum, m = mass of the body and v = velocity of the body.

The law of conservation of momentum can be explained from Newton's Second Law of Motion which states- " the rate of change of linear momentum of a body is equal to the net external force applied to it i.e. 

\(\frac{d{p}}{dt}=\frac{d(m{v})}{dt}\Rightarrow m\frac{d{v}}{dt}=ma\Rightarrow F_{net}\)

If F_net = 0, ∴  dp = 0 i.e p = constant.