Newton's laws and friction

  • Thread starter Pyae
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  • #1
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Homework Statement



Two blocks are accelerated across a horizontal frictionless surface as shown. Frictional forces keep the two blocks from sliding relative to each other, and the two move with the same acceleration. F = 1.2 N and M = 1.0 kg

Homework Equations



what is the horizontal component (frictional force) of the force of the large block on the small block?


The Attempt at a Solution


Homework Statement





Homework Equations





The Attempt at a Solution


Homework Statement





Homework Equations





The Attempt at a Solution

 

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Answers and Replies

  • #2
2,745
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If the acceleration is the same, then the force must change given the masses are different.

Given F = ma

For the lower block, F1 = 2M*a

For the upper block, F2 = M*a

Where M = 1.0kg and F1 = 1.2N

Given a is equal, you can rearrange the two and solve for F2

Please note you are really supposed to supply an attempt at the solution.

Jared
 
  • #3
3
0
I know the answer is 0.4 N to the right. I don't know how it gets. But here's what i'm thinking.

i think the given F applies to both blocks, so

F= ma
1.2 = 3M * a
a = 0.4

then F1 = ma = 1 * 0.4 = 0.4 N

I don't know if it makes sense. Can someone give idea and guidance on how to solve this problem?
 

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