Q: can another computer access a time machine backup and files?

I have a dead HD on a macbook pro.  Fortunately (I think), I use time machine automatically.  Unfortunately, I always got my time machine passwords from Keychain.

1) If I replace the HD, will it automatically access Time Machine for backup?

2) Are passwords stored on the HD or in RAM?

3) Can another computer access the Time Machine back up?

Thanks.