Acceleration of two masses and tension.

AI Thread Summary
The discussion revolves around calculating the acceleration of two masses and the tension in a frictionless system. The user struggles with setting up the equations, particularly in determining the forces acting on the masses. Key concepts include understanding tension as an internal force and the importance of free body diagrams for visualizing the forces. The user successfully calculates the normal force for one mass but seeks guidance on proceeding to find the tension for the other mass. The conversation emphasizes the need for a clear understanding of the forces involved in the problem to find the solution.
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Homework Statement


Hi guys, got a bit of a tough problem that i can't seem to solve.

What is the acceleration of two masses and the tension in the string if both surfaces are friction less.


http://img376.imageshack.us/img376/5889/physics.jpg


Homework Equations





The Attempt at a Solution



Now i had another example that i tried to follow but, in that one the force of friction is 9N. I tried to make the following eqn

m2a = -T-m2gsin40 - ( this is where i got stuck, i don't know what to subtract as there is no force given.)

could someone give me an idea where to start? thanks.
 
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Think about (and set up) your free body diagram. You know that tension is an internal force (i.e. it doesn't happen by itself, something causes tension). And you know your system is isolated. Just imagine intuitively, what's stopping the 5kg block from sliding down the ramp if the ramp is very slippery? Is there anything stopping it?

It might also be helpful to think about this system as two dangling weights (i.e. with no surface, therefore no friction) and then think about what the surface does.
 
Him ok so i don't know if this is right but i was able to find out FN by doing this

FN = mg x cos\vartheta = 3kg(9.8m/s2) * cos30
FN = 42.43N

Now from here would i go on to find T1 for the 3kg mass?
 
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