Is this free on a Tuesday to visit museum

I don't think it is free any day. Worth paying to see.

They do free admission on Mondays. You get a ticket online, starting at 7am. It's first come first serve.

You need a ticket...

No

Monday only... I think must register via online inadvance.

Hi you only get in free on a Monday

9/11 Memorial Museum Thur-Mon, 10 a.m. to 5 p.m.

I believe the museum is closed on Tuesdays. But, pretty sure there isn't a free ticket day.