# Block on slope. mechanics.

1. Nov 13, 2005

### Pixter

A wedge with mass M rests on a fricitonsless 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.

q1: calculate the accelration of the wedge

now why would the wedge have any accelration at all? wouldn't just stand still?..

I can't get how I'm suppose to calculate the acceleration of the wedge.

2. Nov 13, 2005

### Just some guy

The wedge exerts a reaction force on the thing on the wedge. From Newton's third law there must consequently be a force on the wedge equal to the normal reaction force. As this force is not perpendicular to the horizontal a component of this force is in the horizontal direction, producing an accelleration on the wedge.

3. Nov 13, 2005

### Pixter

So if the normal force for the block is n the opposite one which is the one that acts on the wedge will be m*g*cos(aplha).. but how do I get the horizontel component for this force?