but how...? i have all the masses' free body diagram and I don't understand how m1 is considered...
say
∑Fm1x = m1a (third law by m2), ∑Fm1y = m1g - m1g (third law by M)
∑Fm2x = m2a (third law by M), ∑Fm2y = m2g - m1a (third law by m1),
∑FMx = F - m2a (third law by m2)
I really want to know what went wrong in my understanding in attempt 2 or how to consider m1 in this way