# Law of conservation of MOMENTUM

Meaning :

Total momentum in an isolated system does not change. the law of physics that states that the linear momentum does not change unless an external force acts upon it.

The law of conservation of momentum explains that momentum is neither lost or gained. "when two bodies collide with one another, the total energy remains constant. That means that the total amount of momentum doesn't change.

Examples :

In a collision or Newton's Cradle. (5 balls hanging on a string, when you move one to hit the other balls, there is a reaction ) . Recoil

Momentum is the concept that links the action of a force and the change of speed it produces. It accounts for the fact that a force will produce a large acceleration in a small mass but a small acceleration in a large mass. If this law was not universal, then the outcomes of identical interactions would vary,contrary to the basic tenets of physics.

Formula :

Total Momentum After Collision = Total Momentum Before Collision

             : m1u1 + m2u2 = m1v1 + m2v2               ----( 1)


Elastic and Inelastic Collisions: ΔK.E. = (Total K.E.)after collision - (Total K.E.)before collision

            : 1/2  (m1u1)^2 + 1/2 (m2u2) ^2 = 1/2(m1v1)^2 + 1/2 (m2v2) ^2    ----( 2)


Combined equation 1 & 2 to form a new formula .

TRY TO COMBINE THEM TO FORM A NEW AND USEFUL FORMULA :)

Note by Nicole Ling
7 years ago

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Oh nice!! The conservation of momentum is really useful sometimes. It seems like common sense, but yeah!! Well explained. (y) I also like the Newton Cradle animation. ^^

v1-u2=u1-v2

- 7 years ago

You can wrote like this too . It's up to you :)

- 7 years ago

[(m2/m1) (u2 - v1)][(u2 + v2) - ((m2/m1) (u2 - v2)) - 2 u1]=0 i don't know if this formula is useful or not but this what i've got by isolating v1 it depends on what data you have been given nice topic to discuss...

- 7 years ago

The formula that you have written is useful too :) It's depend on how you use it and you can think of what types of question is suitable to use the formula that you created... So you can solve the problem easier and faster :)

- 7 years ago

v1 - v2 = u2- u1

- 7 years ago

It's right too :) It's depends on how you use it .

- 7 years ago

Hi Nicole. You must be in Form 5 (SPM)?

- 7 years ago

Ya , How did u know it :) ?

- 7 years ago

I took my SPM in 1984. I am not a 20 year old by a long shot.

- 7 years ago

That's what is required from a 17 year old from Malaysia. (plus I know everything) Haha

- 7 years ago

lol haha

- 7 years ago