Random and stationary objects colliding?

Question

Which is more likely to collide in a given confined space two randomly moving objects or one stationary and one random object?

One trial would consist of two randomly moving objects.

A second trial would be one random object and one stationary object.

Would the placement of the stationary object in the second trial make any difference?

Answer 1

While not sure how one would go about proving it, I would suspect the more likely eventual collision would be between the moving and stationary objects. If there is no loss of momentum when the moving object collides with a wall, then (barring an infinitely-occurring pattern of movement), the moving object will eventually cover the entire interior of the box and intersect with the stationary one. With two moving objects, again the entire interior will be covered, but thye two objects also have to be at the same place at the same time...the possibility that they never meet is much more likely. As to the second question, I should think the closer its placement into one of the corners of the box, the less likely of a collision.