Analytic expression for pull-or-jerk experiment
  This work focuses on a theoretical analysis of a well-known inertia demonstration, which uses a weight suspended by a string with an extra string that hangs below the weight. The point in question is which string, the upper or lower, will break when pulling down on the bottom edge of the lower string at a constant pulling speed. An analytic solution for the equation of motion allows us to identify the critical value of the pulling speed, beyond which the string breaking varies from one to the other. The analysis also provides us a phase diagram that illustrates the interplay between the pulling speed and the string's elasticity in the pull-or-jerk experiment. 
Hiroyuki Shima
physics.ed-ph physics.class-ph physics.pop-ph