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djeitnstine
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Homework Statement
A steel tube with a 32mm outer diameter and a 4mm thickness is placed in a vice and is adjusted so that the jaws tough the ends of the tube without exerting any pressure on them. The two forces shown are then applied to the tube. After these forces are applied, the vice is adjusted to decrease the distance between the jaws by 0.2mm. Determine the forces exerted by the vice on the tube at A and D.
http://img193.imageshack.us/img193/2700/13357119.th.jpg
The Attempt at a Solution
http://img51.imageshack.us/img51/2055/76147557.th.jpg
Ok I did the question and got the answer after the professor solved it in class. However what I do not understand is why does he take the reaction forces as radially outward (in tension) and when he did the solution, he treated left as positive and right as negative.
This seems to go against convention. Even the solution manual has the same technique as he does. His explanation was that [tex]R_a[/tex] was in tension. Clearly from convention its in compression and so is [tex]R_d[/tex]. Their answer also 'miraculously' show that it is in compression.
Anyone can clarify this please?
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