Conservation of linear momentum of a system – Rankers Physics

Definition of Force Inertia and First Law: Practice Problem & Solution

Read the statements marked as assertion (A) and reason (R) and choose the correct option. Assertion (A): If no external force acts on a system, the velocity of the centre of mass remains constant. Reason (R): If there is no external force on system, then momentum of system is conserved.  
Both (A) and (R) are true and (R) is the correct explanation of (A)
Both (A) and (R) are true but (R) is not the correct explanation of (A)
(A) is true but (R) is false
(A) is false but (R) is true

Solution Explained:

To solve this problem, we apply the core principles of Definition of Force Inertia and First Law. Understanding the underlying formula is key to arriving at the correct answer below:

When no external force acts on the system, the acceleration of the center of mass is zero, hence its velocity is constant. This also implies the conservation of total linear momentum of the system.

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