How to Solve an Incline Plane and Pulley Problem?

[temaire]

Homework Statement

http://img216.imageshack.us/img216/1767/inclineplanevq9.jpg​

Homework Equations

F = ma
sohcahtoa

The Attempt at a Solution

The answer to the question is b, but I got a. I used the sine ratio and divided the forces that were acting on mass 1 by the forces acting on mass 2. Can someone help me on this question?

 

[Dick]

That's because the question is so badly written. If you consider positive 'a' to be m2 accelerating down, then a) is correct. If you choose positive 'a' to mean m2 is accelerating up, then b) is correct.

 

[temaire]

Actually, if you put it that way, I don't think that the question is worded badly, because m1g would be greater than the parallel force of gravity, so m2 would be accelerating up. Remember, m1 = m2. Can you explain in further detail how you came to your conclusion though?

 

[Dick]

In working these problems, you get to choose which direction you consider positive. You chose a different and equally valid way to do that. The question should have been clearer on that.

 

[physicsbhelp]

b) is correct.

 

[temaire]

Can you show me how you got b?