Experimental determination of center of mass via suspension

Steps:

• Suspend the lamina from a vertical pin at one point and allow it to hang freely.
• Mark the plumb line (vertical line through the pin) on the lamina.
• Repeat suspension from a different point and mark another plumb line.
• The intersection of the plumb lines locates the center of mass.

Why D is correct:

• The center of mass is the point where the lamina balances, lying along all plumb lines from suspension points, as per the equilibrium condition for torque.

Why the others are wrong:

• A balance compares masses but cannot locate the center without suspension setup.
• B measuring tape only measures lengths, not mass distribution.
• C micrometer gauges small dimensions, irrelevant to mass center.

Final answer: D