For a system to follow the law of conservation of linear momentum during a collision, the condition is : (1)…
For a system to follow the law of conservation of linear momentum during a collision, the condition is :
(1) total external force acting on the system is zero.
(2) total external force acting on the system is finite and time of collision is negligible.
(3) total internal force acting on the system is zero.
(1) only
(2) only
(3) only
(1) or (2)
Solution
From Newton's second law,
$F=\frac{d p}{d t}$
If $F=0$, then $\frac{d p}{d t}=0$
$\Rightarrow \quad p=$ constant
Thus, if total external force acting on the system is zero, then linear momentum of the system remains conserved.