# Experiment 3: Conditions for Equilibrium

1918 Words Sep 27th, 2010 8 Pages
1. Introduction
When we say equilibrium, it is a state of balance. It is a condition where there is no change in the state of motion of a body. Equilibrium also may be at rest or moving within a constant velocity. A simple mechanical body is said to be in equilibrium if no part of it is accelerating, unless it is disturbed by an outside force. Two conditions for equilibrium are that the net force acting on the object is zero, and the net torque acting on the object is zero. Thus, the following objectives were emphasized in this experiment: to determine the equilibrant force using the force table and the component method, to determine the unknown forces using the first condition and second conditions for equilibrium, to locate the centre of
Percent error was computed after.
For activity 3, the group used a circle of diameter 10cm and a square of side 10 cm from the card board. The circle and the square was weighed and recorded as Wc and Ws. The group determined the center of gravity of the composite figure by using the balancing method and composite method. In balancing method, a pen was placed in the middle of the composite figure wherein the plumb method, the group used a string with a coin at the end then hung it from any point and measured where it intersects on the composite figure. Figure 2: Balancing Method Figure 3: Plumbing Method
For activity 4, the group first located the center of gravity of the aluminum bar by balancing it on a pencil. The cylinder used in activity 2 was hung 5.0 cm from one end of the bar. Using the force board, the aluminum bar was supported by means of a spring scale on the end and a string on the other end until the bar assumes a horizontal position. The group used the second condition for equilibrium to determine the weight of the bar and the tension in the string. Percent error was also computed. Figure 4: Set-up for Activity 4

4. Results and Discussion

Activity 1
Tensions Magnitude (N) Position(°)
TA 1.3105 30°
TB 1.7962 200°
Experimental Equilibrant 0.6241 360°
Theoretical Equilibrant 0.5545 356°
% Error 13%
Table 1: Results of Activity 1
Table 1 shows the magnitude and the positions of the equilibrants and the tensions acting on the pans.
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