Object 2
In this object we need to find the centre of mass of the two irregular shaped bars. To find the COM we need to use at least two known masses. As the two known masses, will be used masses of the 10g and 50g.Hence, there will did 4 experiments. First of all, will be explained how each experiment was set up. Then will be shown the Table, which include the raw data during the experiment.
Part A (Experiment 1.1 with the 1st irregular shaped bar)
First of all, will be explained how all system were set up. In the beginning iron stand was connected to the triple beam balance. Then, using light string, bar was randomly connected to the iron beam. Then two known masses hanged to the bar and fixed in position, where whole system was balanced.
The Figure 4, which is above, will give the visual information about how equipment was set up.
Figure 4.
10g
mass
50g
mass
String
Figure 4, shows set up of equipment, but does not show the forces acting on this bar.
Figure 5.
Figure 5, which is above, is shows Free Body Diagram of this bar. Tension force of the string did not shown, because system already in equilibrium.
Where,
is the mass of the bar,
is distance between string and the beginning of the bar,
is a distance between string and
,
is a distance between string and
and
is a distance between centre of mass of the bar and the beginning of
the bar.
Part B (Experiment 1.2 with the 1st irregular shaped bar)
As in the Object 1, before using formula (2), experiment should be done two times. In the second experiment bar was hanged in different point. Masses also were hanged to other points. Therefore, all system must be in equilibrium. Figure 6, below, will give visual information about, how bar and masses were hanged.
Figure 6.
String
How can be clearly seen in the Figure 6, the masses are in different place. Then, to get more information and show where the forces acting to the bar, will be done Free Body Diagram. Figure 7, above, is the free body diagram, which show all forces acting on the bar.
Figure 7.
Where, is the mass of the bar, is distance between string and the beginning of the bar, is a distance between string and , is a distance between string and and is a distance between centre of mass of the bar and the beginning of the bar.
Part C (Raw data and calculating)
During the Experiment 1.1 and Experiment 1.2, were recording data. Data are sorted in the Table 3 for the length and Table 4 for masses.
Table 3.
Distance (cm) |
Experiment 1.1 |
Experiment 1.2 |
From 0cm to string |
41.7 |
37.3 |
From to string ( ) |
12.8 |
35.3 |
From to string ( ) |
29.7 |
22.3 |
From COM to string |
-41.7 |
-37.3 |
Table 3, shows what distance was between string and masses and COM.