[ام عبد الرحمن محمد]

T1 = M1 g
T1 = 2 *9.8 = 19.6

T2 = M2 g

T2 = 3 * 9.8 =29.4

T1 cos 30 = T2 cos o
19.6 * .866 = cos o*29.4
o = 54.7
o هي الزاوية
T1 sin 30 + T2 sin 54.7 = m3 g
19.6 * 0.5 + 29.4 * 0.82 = m3 * 9.8
m3 = 3.5