# Momentum!

AThousandYoung
Posers and Puzzles 31 Mar '09 02:46
1. AThousandYoung
All My Soldiers...
31 Mar '09 02:46
Two objects with masses M and m are stuck together and accelerated to a velocity v1 in a vaccuum with no gravity. As they travel, they separate, and continue forward separately.

Do the two objects continue forward at the same speed or do they each get a different amount of momentum due to their different masses?

The system I am examining is the Armor Piercing Fin Stabilized Discarding Sabot tank round.
2. coquette
31 Mar '09 04:01
Originally posted by AThousandYoung
Two objects with masses M and m are stuck together and accelerated to a velocity v1 in a vaccuum with no gravity. As they travel, they separate, and continue forward separately.

Do the two objects continue forward at the same speed or do they each get a different amount of momentum due to their different masses?

The system I am examining is the Armor Piercing Fin Stabilized Discarding Sabot tank round.
How do they objects that are "stuck" together come apart?

Okay, forget that, because it doesn't change their V1, or it would have been included in the problem statement.

Neither changes from V1 if there is no force upon them, and in your problem there is not force on either of them.
3. AThousandYoung
All My Soldiers...
31 Mar '09 05:121 edit
Originally posted by coquette
How do they objects that are "stuck" together come apart?

Okay, forget that, because it doesn't change their V1, or it would have been included in the problem statement.

Neither changes from V1 if there is no force upon them, and in your problem there is not force on either of them.
Hmm. Well in the case of the APFSDS round, it's air resistance that pulls the sabot off, but in this example I said vaccuum. Sigh.

All this time I thought my physics skills gave me secret insight into these projectiles, but I guess I was deluded.
4. 31 Mar '09 06:44
Originally posted by AThousandYoung
Two objects with masses M and m are stuck together and accelerated to a velocity v1 in a vaccuum with no gravity. As they travel, they separate, and continue forward separately.

Do the two objects continue forward at the same speed or do they each get a different amount of momentum due to their different masses?

The system I am examining is the Armor Piercing Fin Stabilized Discarding Sabot tank round.
This is actually a problem that Gallileo Gallilei thought about. At that time, they thought, heavier objects was falling faster than lighter ones. Then he did the experiment from the leaning tower in Pisa, he let go two objects at the same time from the top of the tower, one heavy and one light, and they reached the ground at the same time. From then on we know that mass has nothing to do with the objects accelleration.

Some people say that the experiment of Gallieleo wasn't done, but was referred to as an experiment in mind and got the result from pure reasoning. I don't remember the reasonng, but when I read about it, it made perfectly sense.
5. forkedknight
Defend the Universe
31 Mar '09 20:48
Originally posted by AThousandYoung
Two objects with masses M and m are stuck together and accelerated to a velocity v1 in a vaccuum with no gravity. As they travel, they separate, and continue forward separately.

Do the two objects continue forward at the same speed or do they each get a different amount of momentum due to their different masses?

The system I am examining is the Armor Piercing Fin Stabilized Discarding Sabot tank round.
If an identical force was exerted on both objects, the heavier object would accelerate/decelerate slower due to increased momentum. As is, however, both objects would continue at V1, as already stated.
6. 01 Apr '09 02:26
Momentum is directly proportional to both velocity and mass.

So at the same velocity, the more massive object will have greater momentum (and thus require more force to stop).