Can I hang 100lb boxing bag from wood ceiling beam?
I've hung a few heavy items in cases like this by installing 4"x4" or 6"x6" joist hangers facing each other between two joists and installing the appropriate beam into them. Then drill through the beam, install an eye bolt with washer and nut on the back. Hang the item.

This is similar to what I did but I used a 6x6 and ran my eye bolt all the way through.