Please verify this notion regarding ..... momentum

[inquisitive]

Hello. Could someone verify this notion about momentum.... thanks

here is info:
- The conserved closed system here, is a vehicle and the planet (via the road attached)
- A stationary vehicle has no momentum
- A moving vehicle has some momentum

here is point to verify:
A moving vehicle has created a quantity of momentum (forward direction for vehicle) AND it has created a quantity of momentum (opposite direction for planet)
* So... the total quantity of momentum is exactly half each?
As p=mv
* So... the vehicle will have very small m and large v quantity
* So... the planet will have large m and very small v quantity

I wish to know if I can correctly state...... the total quantity of momentum is half each (for vehicle and planet)

[this is linear momentum and no other factors effect the closed system]

much appreciate thoughts, cheers

[John Cuthber]

The two items have equal momentum, but it's not really half. (Half of what?)

The amount "created" is zero because you can't create something which is conserved.

 

It's a bit like if you lend me $10

The total amount of money we have (added together ) is still the same- none has been created and you couldn't say we each have half the debt.

But I owe $10 and (in a mathematical sense) you owe $-10

[inquisitive]

The two items have equal momentum, but it's not really half. (Half of what?)

The amount "created" is zero because you can't create something which is conserved.

 

Thanks for reply John..... appreciate the half n half.... doesn't carry a reference to one being an opposite (direction)

 

Perhaps this phrase?.... for the same closed system.

Any momentum present (for vehicle and planet) will be exactly equal in quantity, but exactly opposite in direction

[swansont]

Momentum is conserved for any system if the net external force on it is zero.

 

So if you look at a two-component system in the zero-momentum frame, that means that p₁ + p₂ = 0

 

Those are vectors, so the equation means p₁ = p₂ and the directions are opposite.