How do I (re-) start falling objects

Hello

I have following problem:

Example:

I create a ball which will fall on a slide and then sliding down. At the end of the slide there is a gate. At the gate the ball stops. When i open the gate (move the gate back/away), the ball doesn't fall again. It stays in the air.

All objects have the physics behavior.

Any idea?

Thx

Sorry for by bad english. Hope you understand my problem.

From the Physics in Construct 2: The basics

"Note that objects which have come completely to a stop, and are not moving or rotating at all, are "put to sleep" by the simulation. Then, they don't need processing any more. If the object is hit by another one it "wakes up" and starts using processing again."

You could apply an impulse when physics is "sleeping" adding any another conditions if wanted..

Thank you. It work's.