@bkboggy I should've probably specified this, but I'm using vector quantities (rather than magnitudes of forces) to make Newton's 2nd Law an actual sum.
You said ΣFy = T1 + Fg = m1*a. That's wrong. Tension and weight are opposites of each other in this scenario. It should be ΣFy = T1 - Fg = m1*a or ΣFy = Fg - T1 = m1*a, depending on your coordinate system (whether down or up is positive).
@bkboggy I should've probably specified this, but I'm using vector quantities (rather than magnitudes of forces) to make Newton's 2nd Law an actual sum.
You said ΣFy = T1 + Fg = m1*a. That's wrong. Tension and weight are opposites of each other in this scenario. It should be ΣFy = T1 - Fg = m1*a or ΣFy = Fg - T1 = m1*a, depending on your coordinate system (whether down or up is positive).