# Center of Mass and Linear Momentum

1.Two particles lie on an x axis, particle 1 at x = 1 m and particle 2 at x = 2 m. If you gradually increase the mass of particle 1, what happens to the center of mass of the two-particle system?

2.If an external force acts on a system of several objects, can the external force change the net momentum of the system?

((m2)/(m1+m2))d

## The Attempt at a Solution

I'm not sure for the first question if it moves in the negative or positive direction of x or if it does not move at all..

Last edited:

mfb
Mentor
I'm not sure for the first question if it moves in the negative or positive direction of x or if it does not move at all..
Just calculate the position for a small and a large mass of particle 1, and you will see what happens.

Hi iAmKhanz

You should be able to work this out without doing any calculations.
Just think about what the centre of mass means

i think i would think of the center of gravity of two objects on a teeter totter and use that to think of the the two objects one an x axis, . and which way the pivot point would have to move if one object increased its mass, . . don't take my word for it, its been a very long time since i was in school, . . but it also would seem that the center of mass and center of gravity if all objects were constant would be interchangable, . . If im wrong, . hopefully someone will correct me. . . . maybe i also misunderstood the question

question 2 i would then think of two round objects sitting on the teeter totter both on the same side with it at rest and at zero momentum, . . then your finger "External Force" pushing down on the high empty side and seeing if the system changes momentum, ... . again, . its been a long time, and im not sure of all of the frame of reference as to your study, . if someone again will let me know if this is wrong or right i would appreciate it, .. not only for mfb's benefit, but also my own, . .thx