A force problem that seems easy but hard

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The problem involves two blocks of different masses connected by a string over a frictionless pulley, moving on a wedge inclined at an angle. The participants are tasked with determining the acceleration of the blocks and the tension in the string.

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Approaches and Questions Raised

  • The original poster attempts to set up equations based on the forces acting on each block but struggles to isolate the acceleration. Some participants suggest simplifying the approach by reconsidering the direction of tension for the copper block.

Discussion Status

Participants are exploring different interpretations of the forces involved, particularly regarding the direction of tension and the need for normal force considerations. There is an ongoing exchange of ideas, but no consensus has been reached on the best approach to solve the problem.

Contextual Notes

There is mention of a diagram that may provide additional context, but it is not visible to all participants. The problem involves assumptions about the coordinate system and the forces acting on the blocks.

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A 2.00-kg aluminum block and a 6.00-kg copper block are connected by a light string over a frictionless pulley. The two blocks are allowed to move on a fixed steel block wedge (of angle 30.0) as shown in Figure P4.53. Making use of Table 4.2, determine (a) the acceleration of the two blocks and (b) the tension in the string.

My work so far:
For the aluminum block - I got T = 2a, which I cannot solve
For the copper block - I got Tx-58.8sin(30) = 6a - this is for x direction
and
Ny-58.8cos(30) = 6a - this is for y direction

58.8 is the weight force, which comes from 6*9.8 = 58.8N
T = tension force
N = Normal force

All the equations won't get me to solve for acceleration for either blocks

Thanks~~

If you cannot see the attachment, you may click http://students.washington.edu/cy1126/P4.53.jpg"
 

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You don't need an x for the direction of T for the copper block since you are resolving it along the surface of the plane. Once you get this, its semple simultaneous equations.
 
QuantumCrash said:
You don't need an x for the direction of T for the copper block since you are resolving it along the surface of the plane. Once you get this, its semple simultaneous equations.
I see what you are saying, but for the copper block, I defined the x-axis to be the the ramp. Therefore, the coordinate diagram is a slanted one, not a standard one. As a result, you need Tx
 
Neither block is accelerating in the y as you have defined it. Tension is purely in the x. You then get 2 equations with 2 unknowns because the tensions and accelerations are equal
 
If I get what you mean, you should not do that becaus you would need to take into account the normal force.
 

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