Center of gravity aligns vertically below suspension point in equilibrium

Steps:

• For a freely suspended object at rest, the center of gravity (CG) must lie directly below the pivot to minimize potential energy and ensure stability.
• The horizontal pin acts as the pivot, so draw an imaginary vertical line downward from the pin.
• Locate the crosses on the card relative to this vertical line using the diagram.
• Cross C intersects this line, marking the CG.

Why C is correct:

• The CG is the point where the object's weight effectively acts; positioning it directly below the pin results in zero net torque, satisfying rotational equilibrium per Newton's laws.

Why the others are wrong:

• A: Offset left of vertical line, producing unbalanced clockwise torque and rotation.
• B: Not on vertical line, causing tilting away from equilibrium.
• D: Offset right of vertical line, producing unbalanced counterclockwise torque.

Final answer: C