Underneath which spot on a 12-inch ruler could put your finger so that it would balance on your finger and not fall either left or right?

Answer 1

To balance a ruler on your finger, you need to find its center of mass. For a uniform 12-inch ruler, the center of mass is located at the midpoint. Since the ruler is 12 inches long, the midpoint would be at 6 inches from either end.

Therefore, you should place your finger underneath the 6-inch mark on the ruler to balance it so that it does not tip to either side.