Question

h t t p : / / w w w . j i s k h a .c o m / d i s p l a y . c g i ? i d = 1 25 2 8 8 8 9 2 9

ok hmmm

m2 g = m1 (acceleration radial)

so then if this is the correct equation my question... is how do you know when to consider the masses as a system and when not to?

net force = mass times acceleration

by deffintion
it dosen\'t mean this necessarily

net force = net mass times acceleration

when do I know when I should use the net mass and when not to as I have gotten points taken off before because i didn\'t use the net mass and am not sure when to consider the masses as one system and when not to...

like how come this is wrong

net force radial = (m1 + m2) (acceleration radial) = force of gravity on m2

and this is right

net force radial = m1 (acceleration radial) = force of gravity on m2

I need help on when to make this distinction between the masses and when not to as I don\'t know when i should...

THANKS!!!
This has been eating me away and I need to know this or the whole problem is wrong so it\'s important that I know when to make this distinction and when not to. So can you tell me when I should and when I shouldn\'t???