Posted by cinthia on Saturday, May 14, 2011 at 6:00am.
how to find the tension in two strings, 0.75 kg meter stick is supported at the 10 cm mark and the 75 cm mark by strings. a 3.5 kg is at the 25 cm mark and a 2.5 kg is at the 90 cm mark.

Physics  drwls, Saturday, May 14, 2011 at 6:12am
Total tension on the two strings is the sum of all weights.
T1 + T2 = (0.75 + 3.5 + 2.5)*g = 66.2 N
For tension T2 (at the 75 cm mark), set total moment about the other stiring suipport point equal to zero.
T2*65  7.35*40 + 34.3*15 + 24.5*80 = 0
Each term is the product of a force and a measured distance from the 10 cm mark. Negative terms are clockwise moments. The 7.35 N (0.75 g) weight force is applied at the center of mass of the meter stick.
Solve for T2. Then get T1 from the sum.