Two blocks sliding on top of each other

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SUMMARY

The discussion centers on calculating the coefficient of friction required to prevent a 4 kg block from sliding on top of an 8 kg block, both subjected to a 30 N force on a frictionless table. The user initially calculated the acceleration of the bottom block and determined the necessary frictional force to maintain the top block's position. However, confusion arose regarding the nature of friction as a force that can facilitate movement rather than merely resist it. The correct approach involves understanding that friction is essential for the top block to accelerate with the bottom block.

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pharoh123
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A 4 kg block is placed on top of a 8kg block, placed on a table with no friction,which is subject to force of 30N. What is the coefficient of friction needed between the two blocks so that the the top doesn't slide on the other one?

What i did was find the acceleration of the bottom block and then i found the force needed to push the top block at that acceleration. I considered that force the friction and found the coefficient. However, I don't think i got it right since i thought friction couldn't actually move an object and is only a resistance. So did i get right or not?
Thanks
 
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Welcome to PF :smile:

pharoh123 said:
did i get right or not?

If you show your work, we can tell you. At the very least post your answer, but showing the entire work is better.
 

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