Solve Physics Homework: Forces & Friction | Get Expert Help

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The discussion focuses on solving two physics problems related to forces and friction. For problem #7, it emphasizes drawing the string attached to a hook and understanding that the weight of the picture is supported by the vertical components of the tensions, while the horizontal components pull inward. In problem #8, it suggests creating free body diagrams for each mass, noting that the tension in the string is uniform due to the pulley having no mass. The discussion highlights the need to write equations for the unknown tension and acceleration to solve the problems simultaneously. Overall, the thread provides guidance on approaching physics problems involving tension and free body diagrams.
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I am having trouble solving this for my physics homework. Please help with these two problems!

http://img151.imageshack.us/img151/5049/scan1wd3.jpg

I just don't know where to start... please guide me..
 
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For #7, draw the string attached to the hook using the angles given. Assume the picture hangs evenly and the strings are attached to the picture symmetrically so each end of the string supports the same weight (this is implied by the stated angles). The weight of the picture is supprted by the vertical components of the tensions. The horizontal components of the tension pull inward on the edges of the picture.

For #8 draw a free body diagram for each mass. Since the pulley has no mass, the tension in the string is uniform. Each mass will move the same distance with the same speed and the same magnitude of acceleration. You should be able to write two equations involving the unknown tension and the unknown acceleration, and solve them simultaneously for both variables.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
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