*61.  The drawing shows box 1 resting on a table, with box 2 resting on top of box 1. A massless rope passes over a massless, frictionless pulley. One end of the rope is connected to box 2, and the other end is connected to box 3. The weights of the three boxes are W1 = 55 N, W2 = 35 N, and W3 = 28 N. Determine the magnitude of the normal force that the table exerts on box 1.

Sum of forces in the y for each block

 

Since there is no motion in the y direction.

 

 

 

 

 

So use this for the T in the second equation

 

Now use this for N2 in the first equation

 

 

 

 

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This page last updated on January 11, 2020