Two skaters A and B of masses 50 kg and 70 kg respectively ,stand facing each other,6 meters apart on a horizontal smooth surface.They pull a rope stretched between them.How far has each moved when they meet?
I just dunno where to start.
Do we apply Newton's third law here?

Question

Two skaters A and B of masses 50 kg and 70 kg respectively ,stand facing each other,6 meters apart on a horizontal smooth surface.They pull a rope stretched between them.How far has each moved when they meet?
I just dunno where to start.
Do we apply Newton's third law here?

irishboy123 · Answer

they'll meet at their current centre of mass.

cos there is no external force on the system , ie the skaters, newton's second says that F = ma = 0

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so take moments about a suitable point :p