You know, don't push the button, don't push the button, don't push the button, and then some socko finish. I was pleasantly surprised by how the book bobs and weaves and is a lot more active and entertaining that just that. MILD SPOILER, so don't tell your four year old.
The late payment penalty applies to any portion of your federal tax that remains unpaid as of the due date, typically the tax filing date. The IRS imposes a failure-to-pay penalty of one half of one percent for each month or part of a month that the tax goes unpaid.
Teachers, trainees, and researchers in H-1b status are liable for social security/Medicare taxes from the first day of U.S. employment, regardless of whether they are nonresident or resident aliens, and regardless of whether their wages may or may not be exempt from federal income taxes under an income tax treaty.