Conservation of Movement Amount
Like mechanical energy, the amount of movement is also maintained when there are no dissipative forces, ie the system is conservative, closed or mechanically isolated.
A system is conservative if:
So if the system is conservative we have:
Since the mass of a body, or even of a system, hardly varies, what changes is their speed.
A body of 4kg mass travels at a constant speed of 10m / s. Another 5kg mass body is launched at a constant speed of 20m / s towards the other block. When the two clash, they will be caught by a velcro at their ends. How fast will the united bodies be?