Torque on a stick?

Question

A stick is placed on a fulcrum so that 20 cm are on the left and 60 cm are on the right. Two identical balls are placed on the stick. One is at the end of the 20 cm on the left and the other is 10 cm from the fulcrum on the right. What is the ratio of the weight of the stick to the weight of a ball. (Maybe a diagram will help)
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(Sorry, It's the best i could do)

Answer 1

Let b be the weight of a ball, and p be the weight per cm of the stick (thus, the weight of the 80 cm stick is 80p). The torque generated by the stick is thus [-20, 80]∫-px dx. The torque generated by the two balls is b*20 - b*10. If the stick is balanced, the sum of these torques must be zero. Thus:

20b-10b + [-20, 80]∫-px dx = 0
10b + (-1/2px²)|[-20, 80] = 0
10b - 3200p + 200p = 0
b-300p=0
p=b/300
80p = 80b/300 = 4b/15

Thus, the weight of the stick is 4/15 the weight of a ball.