Determine the center of gravity of a uniform wooden bar using a triangular prism as a pivot. Include a diagram, method, and precautions.

Here's how to determine the center of gravity of the uniform wooden bar:

Diagram (2 marks)

\text{ \begin{tikzpicture} % Bar \draw[thick, fill=brown!30] (0,0) rectangle (10,0.5); \node at (5, 0.75) {Wooden Bar (100 cm)}; \node at (0, -0.2) {0 cm}; \node at (10, -0.2) {100 cm}; % Prism (fulcrum) \draw[thick, fill=gray!30] (4.5,-0.5) -- (5.5,-0.5) -- (5,0) -- cycle; \node at (5, -0.75) {Triangular Prism}; % Center of Gravity \draw[dashed] (5, 0.5) -- (5, -0.5); \node[below] at (5, -0.5) {Pivot Point}; \node[above] at (5, 0.5) {Center of Gravity}; \node at (5, -0.2) {50 cm}; \end{tikzpicture} }

Method/Precaution (4 marks)

• Method:
  1. Place the triangular wooden prism on a flat, stable surface.
  2. Carefully place the uniform wooden bar on the prism.
  3. Adjust the position of the bar by sliding it along the prism until it balances perfectly horizontally without tilting to either side.
  4. Once balanced, mark the point on the bar that is directly above the pivot point of the prism.
  5. Use the metre rule to measure the distance from one end of the bar to this marked point. This distance represents the position of the center of gravity.
• Precaution:
  • Ensure the wooden bar is uniform to guarantee its center of gravity is at its geometrical center.
  • Ensure the prism is stable and does not wobble during the balancing process to get an accurate pivot point.
  • Avoid parallax error when reading the metre rule to ensure precise measurement of the center of gravity's position.

Observation (2 marks)

The uniform wooden bar balances horizontally when supported at its midpoint. For a 100 cm bar, this balancing point is observed to be at the 50 cm mark from either end.

Inference/Conclusion (2 marks)

The point at which a uniform object balances freely is its center of gravity. For a uniform wooden bar, the center of gravity is located at its geometrical center. Therefore, the center of gravity of the 100 cm uniform wooden bar is at 50 cm from either end.