Acceleration of a system with 2 Blocks and a Wedge

AI Thread Summary
The discussion centers on a physics problem involving two blocks and a wedge, focusing on calculating accelerations based on varying coefficients of friction. Block B, resting on wedge A, is connected to block C via a pulley, and the goal is to determine the conditions under which the wedge remains stationary. Participants express confusion about the forces acting on wedge A and whether the accelerations of blocks B and C can be considered the same. There is debate over the appropriateness of using different axes for analyzing the motion of the blocks, with some arguing it simplifies finding the normal force. The conversation emphasizes the need for clarity in calculations and the importance of sharing work for better understanding.
goukishin
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Homework Statement


Block B of mass 10 kg is initially at rest as shown on the upper surface of a 20-kg wedge A which is supported by a horizontal surface. A 2-kg block C is connected to block B by a cord which passes over a pulley of negligible mass. Using computational software and denoting by m the coefficient of friction at all surfaces, use this program to determine the accelerations for values of m $ 0. Use 0.01 increments for m until the wedge does not move and then use 0.1 increments until no motion occurs.
Capture.png


Homework Equations


ƩF = ma
Tc/Tb = e(μ x β) (In this case β = 120*pi/180

The Attempt at a Solution


Taking each block as a system, finding Tc then Tb in terms of μ
Assuming the acceleration of Block C is the same as the acceleration of block B

Stuck at studying Wedge A. What are the forces acting on it and the equations?
Is the acceleration of the wedge the same as the acceleration of B?
 
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goukishin said:
Stuck at studying Wedge A. What are the forces acting on it and the equations?
Is the acceleration of the wedge the same as the acceleration of B?
What forces do you think are acting on it?
If B is sliding on A, it will have a different acceleration; otherwise it will be the same.
 
Can we chooses different axes to study Block B and wedge A ?
 
You can, but it might be confusing, particularly for anyone trying to check your work.
 
Well no, it is not confusing, it's the opposite. When we choose different axes according to the position of each block, it is much easier to find the Normal force acting on the system and the acceleration since a(y) becomes zero. But since Block B is in contact with the wedge, I wonder if that's allowed. And I really doubt it.
 
Sounds like you and I mean different things by 'using different axes'. pls post your working so that I can get some idea of what you're doing.
 

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