9.4 Static Equilibrium Center of Gravity |
| Instructions: Click on the "Start Simulation" button to open the applet window. The applet starts automatically with the system in equilibrium. You may move blocks horizontally by dragging them. The color of the blocks indicates their equilibrium state. The green color is used for systems in stable equilibrium. The yellow color is used when the center of gravity lies just above the edge of the supporting surface. The red color designates unstable blocks. Red blocks would fall in real life. Try to reposition the blocks so that the top block lies entirely beyond the right edge of the table. The percentage on the top right of the block indicates how close you are from that target. Red numbers to the top left of the block show the horizontal position of that edge. The blue number in the middle of the block indicates the horizontal coordinate of the center of gravity of that block. Clicking "Show c.g." invokes arrows to show the center of gravity of each block as well as the center of gravity of all four blocks and the center of gravity of the top two blocks. The coordinates of the mouse are given in the text field on the top of the applet. Navigation: You can come back to this window by pressing the "Close Simulation" button on the bottom frame of the utility. |
| Explanation: As explained in section 9.4, individual blocks or sets of blocks will behave as if their mass were concentrated at their center of mass. A block is in stable equilibrium when the torque due to its weight is zero. This is accomplished when its center of gravity (here equivalent to center of mass) is above the supporting surface. This is true for a single block and for several blocks. |
| Source: Fu-Kwun Hwang Go to the web site and link to the Online Library for further information. |