law of conservation of momentum with collision?

Russ Kiernan: ok,the law states that in an isolated system,total momentum before collision is equal to total momentum after collision. Workout some examples and you will find this to be true

Hans Sachetti: in case you're talking a pair of friction-much less atmosphere/atmosphere then you definately won't be able to. in any different case turn the spaceship off? or regardless of in case you're making a spaceship give up going? yet even then it would slow with the aid of friction with the ambience.

Bob Pucella: momentum is equal to mass x velocity.the law of conservation of momentum states that the total momentum in a system always remains the same.if a car collides into a stationary vehicle:before the collision, the momentum is equal to only the momentum of the moving car, because the stationary car has no velocity, and therefore no momentumafter the collision, the two objects "stick" together and move with one total velocity.because the mass of the two cars to! gether is greater than the mass of the moving car by itself, it must be true that the velocity is now less than the car was moving before. (of course the car that was stationary has a greater velocity than it had before because it wasn't even moving)the formula for this situation, if you had numbers, would be:m1v1 + m2v2 = (m1 + m2)v3the left side is before, the right side is afterrememer that v2 = 0if a car collides into a car moving in the same direction:before the collision the car that is behind is traveling at a faster velocity than the car in front, because thats the only way that it can even catch up with the other car.what happens after the collision is that the cars will stick together and move at one velocity. this velocity will be somewhere in between the initial velocities of the two cars (for example, if one of them had v = 1 and the other had v = 2, then the velocity of them after the collision would be between 1 and 2)if you had numbers you would use the same! formula as the first exampleif a car collides into a car movi! ng in the opposite direction (towards it):this would depend on the velocity of each car in comparison to the other.if the cars were traveling at the same exact speed, then they would both stop after the collision.if they were traveling at different speeds, then the cars would move in the direction of the car that was moving faster, but at a slower speed than before. again, with numbers you would have the same formulahowever, you have to remember that you have to choose a positive and negative direction.this is vital because the cars are moving in different directionshope this helps!...Show more