Question

state and prove the law of conservation of momentum. Give any two examples​

Answer 1

Answer:

linear momentum{p bar}=m×a

if two objects of different masses have same momentum, the lighter body possess greater velocity, p=m1v2= m2v2

Answer 2

Law of conservation of momentum :-

When two (or more) bodies act upon one another, their total momentum remains constant (or conserved) provided no external force are acting.

This law can be stated as :-

Momentum is never created or destroyed.

Example :- We can also say that the rockets and jet aeroplanes work on the principle of conservation of momentum.

Prove :-

i) When the force F₁ of the truck acts on the car for a time t, and the velocity of car is given by :

→ a₂ = (v₂ - u₂)/t

But,force = mass × acceleration, so the force F₁ exterted by the truck on the car is given below :

→ F₁ = m₂ × (v₁ - u₁)/t ........1)

ii) When the force F₂ of the car reacts on the truck for a time t,then the velocity of the truck changes from u₁ to v₁. So,

→ a₁ = (v₁ - u₁)/t

But, force = mass × acceleration, so the force F₂ exterted by can on the truck is given below :

→ F₂ = m₁ × (v₁ - u₁)/t .......2)

→ F₁ = - F₂

Now putting the values of F₁ and F₂ from (1) and (2), we get :

→ m₂ (v₂ - u₂)/t = - (m₁ - u₁)/t

Cancelling t from both sides,we get :

→ m₂ (v₂ - u₂) = - (m₁ - u₁)

→ m₂v₂ - m₂u₂ = - m₁v₁ + m₁u₁

→ m₂v₂ + m₁v₁ = m₂u₂ + m₁u₁

→ m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

.°. Total momentum before collision = Total momentum after collision

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