Answer:
The "trolleys" did not collide with each other because their poles repelled.
Explanation:
Magnets have poles located at their ends and these are the "north pole" and the "south pole."
If the north pole of one magnet will be faced to the south pole of another magnet, they will attract each other or pull towards each other. The opposite will happen when the south pole of one magnet will be faced with the same pole from another magnet. They will repel each other or pull away from each other.
Since the magnets attached to the trolleys were U-shaped, this means that the north and south poles are located at the end of the magnets, which face the same direction. So, once the magnets of the two trolleys move towards each other, their poles will repel because same poles will face each other.
So, this explains the answer.
