Calculating Acceleration in a Wedge-Block System on a Frictionless Table

[oldspice1212]

A wedge with mass M rests on a frictionless horizontal table top. A block with mass m is placed on the wedge. There is no friction between the block and the wedge. The system is released from rest.

Figure http://tinyurl.com/9zcf7uq

1. Calculate the acceleration of the wedge.
Express your answer in terms of M, m, $\alpha$, and constant g.

2. Calculate the horizontal component of the acceleration of the block.
Express your answer in terms of M,m, $\alpha$ , and constant g.

3. Calculate the vertical component of the acceleration of the block.
Express your answer in terms of M,m ,$\alpha$ , and constant g.

Answer I got but it was wrong not sure if I'm putting it in right or it's just wrong.

1. -(mgsin2($\alpha$)/2M

 

[Sourabh N]

Can you take us through your solution so we can tell what is wrong?

 

[oldspice1212]

Well I listed the forces first 1, 2, 3 F1: parallel F2:perpendicular and up F3 perpendicular and down

mgsin($\alpha$)
mgcos($\alpha$)
mgcos($\alpha$)

which got me the acceleration

 

[Sourabh N]

I don't understand. Which object are those forces on? What is F1 parallel to?

 

[oldspice1212]

Parallel to F2 lol, it's hard for me to explain I wish I knew how to put a diagram on here

 

[Sourabh N]

You can take a picture of your solution from your notebook, etc. and attach it here. Alternatively, you can click on 'Go Advanced' button underneath this box and type out yoru solution in latex.

 

[oldspice1212]

Err, well how would you do number 1?