# Inclined plane acceleration

1. May 10, 2010

### leonidas24

Consider the classical physics problem of a cube sitting atop a frictionless inclined plane. Of course, this cube will accelerate down the plane with acceleration dictated by F = mgsin(theta), where theta is the angle between the inclined plane and the horizontal surface.

Easy enough.

Now, my question is this; if the inclined plane was itself sitting atop a frictionless, horizontal plane, would it too accelerate in some direction as the cube slides down its surface? In order to conserve momentum, for instance?

2. May 10, 2010

### sophiecentaur

Just write out the force equation and that should do it. Have faith, my lad! Physics works.

3. May 10, 2010

### jack action

The cube would have a simple vertical free fall and the inclined plane would move out of its way as the cube goes down since it doesn't have any restriction.

4. May 10, 2010

### Staff: Mentor

Of course.

The cube is not in free fall. The incline exerts a force on it.

5. May 10, 2010

### sophiecentaur

The cube and the ramp will move apart horizontally - Newton's Third Law - in addition to the cube moving vertically.