Question

write down an expression for the law of conservation of momentum when the body of mass m1 moving with and initial velocity u1 collides with a body of mass m2, moving with initial velocity u2 in the same direction. after collision their final velocities become v1 and v2 respectively​

Answer 1

Answer:

Law of conservation of momentum states that total momentum of system remains conserved in the absence of external force.

Proof:

Consider a body of mass m1 moving with velocity U1, striking against another body of mass m2 moving with velocity U2.

Let the two bodies remain in contact with each other for a small interval "delta t".

Let F12 be the average force exerted by mass m1 on m2, and let F21 be the force on m2 due to m1.

Let v1 and v2 be the velocities of two bodies after collision.

Momentum of mass m1 before collision=m1u1

Momentum of mass m2 after collision=m2u2

Momentum of mass m1 after collision=m1v1

By using the definition of impulse, change in momentum of mass m1 is,