3. Find block weight
a) Use Newton's second law to show that F_T3 = F_T2y
b) Pluggy pluggy to get F_T3 in terms of whatever is in that F_T2 equation (trig required)
c) Use Newton's second law for the hanging block to show that its weight force = F_T3
d) Solve for weight of hanging block. Pluggy pluggy may be required