The sign will hang straight down due to the balanced forces on either side of the attachment point. If the cable is attached to one end, the sign will tilt with the heavier end of the sign pointing downward. If the sign is heavier than the pole, it may cause the pole to bend downward at the attachment point.

A boom is mounted to the bed or the roof of the truck. It is and extendable attachment that can be used to lift workers to the top of a phone or electrical pole, or to a high roofline.

The attachment has become loose.

His attachment to me is a bit creepy.

An attachment can be two things. One kind of attachment is something that can be added to a device, for instance a vacuum attachment tube. Attachment can also mean a special connection, as in "He had an attachment to his favorite horse".

You can read an attachment by left clicking on the attachment, or right clicking on the attachment and left clicking on "Open".