Please some one help me in this **GREAT ***problem in the link below?
UPDATE: If the ratio 3:4 is meant instead of 8:4, it doesn't really change the situation: The ratio should be 1:1. ///////////////////////////////////////. This question seems somewhat mystifying: Using the concept of the Young's modulus, we can see that each stretched bar is similar to a stretched spring. One spring (steel) stretches from the left-hand side to the first bolt; three springs (two copper, one steel) stretches between the bolts; and two springs (copper) stretch from the second bolt to the right-hand side. Since the bolts are not accelerating, the net force on each bolt 0; and that implies that the force stretching each of these segments of springs (one, three and two) are all the same. That means that not only are the push and pull on each bolt the same, but the pushes on both bolts are the same and pulls on both bolts are the same. The bolts are both experiencing the same stress. So the ratio 8:4 doesn't make sense: the tension in the one steel bar is the same as the sum of the tensions in the three middle bars, and is the same as the sum of the tensions in the two copper bars.
