If a worm with length 1 has distance 1 from the left edge of the groove, it will be in range from 1cm to 2cm. if we put the barbell with in distance 2 from left side of groove (left edge of left plate lay on coordinate 2 ) does it squash the worm?

No, because a worm will be lay in range [1,2)

And if just after the barbel? I.e., if the barbel ends at 2, and I put worm at the distance 2, will it squash the worm?

No