Let's say there is a trigger to hit a falling ball. The name of the trigger is Firing Pin.
Every time the Balls falls, the Firing Pin hits the Balls.
Initial force 5000 and [Slider] constraint limits are applied to Firing Pin and it starts with [Frozen] Rigid Body.
If Firing Pin wants to hit Ball 1 first and then reload again to hit Ball 2 then have to return the physical setting of Firing Pin to [Frozen].
And all of this series of processes can never be executed unless Timeline's cumbersome key-frame work is done.
So I propose the development of another tool to replace keyframe tasks for Rigid Body property changes during Physics simulations.
Please refer to the attached images.