Work procedure

1. Connect a device to the mains 220 V and push the button „Сеть”.

2. Remove the pendulum from the support arm 6, release the detent 9 and station the weight 8 center on the distance 10 сm from the suspension point. Measure the distance with the number of known collar marks on the rod from supportive prisms (suspension center) plus 1 сm to the weight which includes the thickness of the load (2 sm). Seek a clear fixing of a load in marks.

3. Hang up the pendulum on the supportive arm 6. Watch after its mounting reliability.

4. Regulate the supportive arm 4 position so that the bottom rod end of physical pendulum 7 won’t catch on photoelectric sensor 5, but block its ray.

5. Activate physical pendulum in oscillations, having rejected it on a corner less than 5^о.

6. After the pendulum make 1 ÷ 2 oscillations, push the button “Сброс”. Counting of time and oscillations number will start which will be visible on corresponding indicators.

7. When oscillations indicator shows up number 9, press the button “Стоп”. The last 10-th oscillation will finish and the stopwatch will stop.

8. Define the period of oscillations, dividing time for oscillations number that is 9. Distance Z and period Т write down to the table.

9. Repeat points 2÷8, removing the weight down in 2 cm to the possibly lowest weight position.

10. Under formula (6.12) calculate Х and write it down to the table. Pendulum parameters are: mass ratio 0,3; Length of the bottom rod end to suspension point а = 5 cm; total rod length b = 59 cm. Calculation it is more convenient to do on the computer.

11. Plot the dependence Y = f(X) and choose two points 1 and 2 on its rectilinear part and define its coordinate by axes, not from the table, on the graph inclination find the free fall acceleration by the formula

, cm/s². (6.13) Compare the received value with reference 980 cm/s². Write the conclusion.

Table 6.1

Z, cm	Y=Z2, cm2	Т, s	Х, cm×s2

Figure 6.4