Frame Rate and Speed
Film Speed = 24 fps
  35mm feature films traditionally run at 24 frames per second. Film speed is governed by the sprocket holes on the film itself.
Production Audio Speed = 30 fps NDF
 

Nagra or DAT tape recorders are electronic by nature; therefore they require 30 frames per second timecode (LTC) recorded on a discrete audio track which serves as "virtual sprocket holes" on the audio tape.

One film frame is the equivalent of 1.25 timecode frames. During telecine (film to videotape transfer) an operator will use the slate from each take to sync audio with picture.
Video Speed = 29.97 fps NDF
  NTSC color video speed is actually 29.97fps, which sounds confusing but is simply 30fps running 0.1% slower.
Video Speed is slower than Film Speed
 

During telecine*, both film and production audio speeds are "pulled down", or slowed down 0.1% while transferring to videotape. Thus, when Nagra or DAT audio is synced with film running at 24fps, the audio is said to be running at "film speed". When played from videotape the audio is said to be running at "video speed".

In the digital audio world, a "pull down" or "pull up" is performed by changing the sample rate. This is selected in both hardware and software on Media Composer and ProTools systems. For example, a sample rate of 44.1kHz pulled down 0.1% would result in a sample rate of 44.056kHz; a pull up would result in 44.144kHz.
  *Nonlinear editing systems typically digitize both sound and picture from videotape. A telecine log keeps track of all the key code numbers, sound roll and videotape timecodes so that when the editing process is complete, the original source media can be conformed to the final edited picture by converting the video EDL. An audio EDL is output with the original Nagra or DAT timecode references.