- #1

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## Homework Statement

There is no friction between any surfaces mass is known. Find acceleration of the blocks.

## Homework Equations

F=ma

## The Attempt at a Solution

I'm almost certian

Amx=g sin θ

AMy=0

- Thread starter VinnieD
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- #1

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There is no friction between any surfaces mass is known. Find acceleration of the blocks.

F=ma

I'm almost certian

Amx=g sin θ

AMy=0

- #2

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Hmm.... Why wouldn't the acceleration in the x direction be affected by the mass of the objects?

- #3

TSny

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Yes, these look correct.Amx=g sin θ

AMy=0

Most of your work looks OK to me.

The part x-ed out in red is incorrect, but it doesn't look like you used that part.

Look at your final equation circled in blue. Can you see a substitution that you can make for ##N_m## in this equation that would allow you to solve for the acceleration of the wedge, ##a_{Mx}##?

One of the key equations for this problem is the constraint ##a_{my} = -a_{Mx} \sin \theta## (boxed in green). But I don't see where you showed how you obtained this.

- #4

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That would be true if the wedge were fixed. But imagine if the wedge were not only frictionless but extremely light. The block would be almost in free fall.Amx=g sin θ

- #5

TSny

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For the block, the x direction is parallel to the incline. So, free fall acceleration would have an x-component of magnitude g sinθ.That would be true if the wedge were fixed. But imagine if the wedge were not only frictionless but extremely light. The block would be almost in free fall.

- #6

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I had not picked up that x was defined as parallel to the slope.For the block, the x direction is parallel to the incline. So, free fall acceleration would have an x-component of magnitude g sinθ.

- #7

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Nor had I, especially since x is specifically drawn in his solution diagram as being the normal horizontal axisI had not picked up that x was defined as parallel to the slope.

- #8

TSny

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But the x-axis is drawn

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