Mechanics > Statics > Center of Mass DCS# ?
CENTER OF MASS OF STUDENT AND BRICKS ON A BOARD

APPARATUS
two 8' boards, 16 lb. each
 107
two lead bricks
 202-04-E
two wooden supports 202-15-C
bathroom scale
 202-15-C

DESCRIPTION
Place the boards on the wooden supports located at the 2' and 6' marks.  A light (<140 lb) student volunteer stands on the board at a distance xs from the end.  Find the minimum xs so that the center of mass of the system is between 2' and 6'. 

Repeat the calculation with two 26-lb. bricks placed at x = 6'.  The new value for xs is less than zero, so the student can walk to the end of the board without tipping it.