Question

define law of conservation of linear momentum ? also derived equation ​

Answer 1

Answer:

Conservation of momentum is a fundamental law of physics, which states that the total momentum of an isolated system is conserved. In other words, the total momentum of a system of objects remains constant during any interaction, if no external force acts on the system.

Explanation:

Derivation of Conservation of Momentum

If no external force is exerted on the system of two colliding objects, the objects apply impulse on each other for a short interval of time at the point of contact. According to Newton’s third law of motion, the impulsive force applied by the first object on the second one is equal and opposite to the impulsive force applied by the second object on the first object.  

During the one-dimensional collision of two objects of masses

m1m1

and

m2m2

, which have velocities

u1u1

and

u2u2

before collision and velocities

v2v2

and

v2v2

after the collision, the impulsive force on the first object is

F21F21

(applied by the second object) and the impulsive force on the second object is

F12F12

(applied by the first object). Applying Newton’s third law, these two impulsive forces are equal and opposite i.e.

F21=−F12F21=−F12

If the time of contact is t,  the impulse of the force

F21F21

is equal to the change in momentum of the first object. 

F21t=m1v1−m1u1F21t=m1v1−m1u1

The impulse of force

F12F12

is equal to the change in momentum of the second object.