Momentum Change in a Collision with Combined Units

[sameeralord]

In this collision


Before= p=100 kg m/s---> <-----p=120 kg m/s
After= <--combined unit P= 20 kg m/s

In this question when I work out the change in momentum for 2 objects it is not the same. When there is a combined unit traveling after the collision can't you find the change in momentum?

 

[phyzguy]

What's the problem? The total momentum is 20 kg-m/s to the left both before and after the collision.

 

[sameeralord]

What's the problem? The total momentum is 20 kg-m/s to the left both before and after the collision.

How do you find the change in momentum of each object? Is the data insufficient?

 

[phyzguy]

I see your question. Unless you know the masses of the two objects, you don't know how much of the final momentum belongs to each object, so you can't calculate the individual changes.