# Homework Help: Wedge on a frictionless table

1. Oct 11, 2012

### 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

2. Oct 11, 2012

### Sourabh N

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

3. Oct 12, 2012

### 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

4. Oct 12, 2012

### Sourabh N

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

5. Oct 12, 2012

### oldspice1212

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

6. Oct 12, 2012

### 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.

7. Oct 12, 2012

### oldspice1212

Err, well how would you do number 1?