Aim: To test the principle of moments.
Apparatus: Metre rule with holes drilled at the 25cm, 50cm and 75cm mark, 50g masses
50mm long bolt with a diameter of approximately 5mm, retort stand, boss head and clamp, 0-10 N spring balance, electronic pan balance ,wire or string for suspending masses from the metre rule, two bulldog clips.
Part A: Balancing a constant moment.
Procedure:
1. The experiment is set up by first placing the bolt through the rule, then the bolt is clamped with the boss-head. The rule must be ensured that it is balances horizontally before adding any weights.
2. The height of the pivot is adjusted so that when the rule is balanced the weights are a few centimeters above the bench top.
3. A 100g mass is hung between the 50cm mark and 100cm mark in a position so that the metre rule is balanced in the horizontal position.
4. The scale on the metre rule is used to measure the distance from the pivot point to the point where the second 100g mass is hung and record this value in the table 2 as shown below, in the column labeled. Distance to weight (cm).
5. Successive 50g masses is added and steps 2 and 3 are repeated for all mass values shown in the first column of Table 2.
Fixed Mass Data | Mas in grams (g) | 100g | Mass in kilograms (kg) | 0.1kg | Distance from pivot (cm) | 45.0cm | Distance from pivot (m) | 0.45m | Weight in newtons (N) | 0.98N | a c moment about pivot (Nm) | 0.441Nm |
Table 1
Table 1
Mass used (g) | Mass used (kg) | Weight used(N) | Distance to weight (cm) | Distance to weight (m) | Weight × Distance (Nm) | 100 | 0.10 | 0.98 | 44.8 | 0.448 | 0.439 | 150 | 0.15 | 1.47 | 29.8 | 0.298 | 0.438 | 200 | 0.20 | 1.96 | 22.8 | 0.228 | 0.447 | 250 | 0.25 | 2.45 | 18.0 | 0.180 | 0.441 | 300 | 0.30 | 2.94 | 15.0 | 0.150 | 0.441 | 350 | 0.35 | 3.43 | 12.7 | 0.127 | 0.436 | 400 | 0.40 | 3.92 | 11.1 | 0.111 | 0.435 | 450 | 0.45 | 4.41 | 9.90 | 0.099