Dynamics Activity
Hanging Wrench Demo


BHS -> Staff -> Mr. Stanbrough -> Physics -> Mechanics -> Newton's Laws -> Newton's First Law -> this page


Demonstrate the difference between mass and weight.


Heavy wrench (or other massive object), string, sturdy support


  2. Tie a piece of string to both ends of the wrench. Suspend the wrench from one string.
  3. Pulling quickly on the bottom string breaks the bottom string.
  4. Pulling slowly on the botton string breaks the top string.


Note: You may have to use some trial and error to find the right strength of string for your mass...

Pulling quickly breaks the bottom string because the inertia (mass) of the wrench causes it to resist sudden accelerations.

Pulling slowly breaks the top string because it must support both the weight of the wrench and to added force.

last update January 6, 1997 by JL Stanbrough (Questions, comments, and suggestions are welcome at jerry_stanbrough@bhs.batesville.k12.in.us)