Work procedure and data processing. 1. Remove loads from the rods.

1. Remove loads from the rods.

2.Measurethe diameter of pulley with trammel. Write down a result as:

m,

where D is an instrumental error of trammel.

3.Write down the value of falling load mass and height, the load falls from as:

kg; m,

where m is an instrumental error of mass measurement; D h is an instrumental error of height measurement.

Value of m, h and m are indicated in the passport of the laboratory work.

4.Let the load go down and measure the time of its falling down to a lower score with a stop watch. Repeat measurement 5 times and enter the results into table 1

Table 1

Position	Ex. No	Load falling down time t, s	Average value tave, s	Distance ,m	Distance lі, m	Height, the load falls from h, m
Without loads
Position 1
Position 2
Position 3

5. Fix loads at the first rods scores near the pulley and carry out measurements according to point 4.

6. Determine distance l_i between the centre of loads and the centre of rotation using the formula:

Enter the result into table 1.

7. Fix loads on a medial, and then on farthest scores of the rods and execute actions suggested in items 4 and 6.

8. Calculate average values and according to the formula (1) determine the moments of inertia of pendulum without loads I₀ and with loads in positions 1, 2 and 3: .

9. Determine random error of falling load time measurement Δ t_r =t_st , where t_st = 2,78 is Student’s coefficient for n = 5 and reliable probability a = 0,95.

10. Calculate the absolute error of time measurement using formula:

11. Calculate the fractional error of the inertia moment I₀ measurement using formula 2. As m, h and D are used instrumental errors.

12. Calculate the absolute error of I₀ determination. Write down the result according to the formula:

13. Calculate inertia moments of the loads in three positions:

14. Plot the graph as the dependence of loads inertia moment upon the square of loads distance to the rotation centre I = f (l ² ). Analyze the obtained graph.

questions to be admitted for doing laboratory work and its defence

1. Give the definition of rotational motion.

2. What kinematical and dynamic characteristics is rotational motion described by?

3. What is moment of force? What does moment of force depend on? Formulate the moment of force direction determination rule.

4. What is physical sense of angular momentum? What does angular moment depend on?

5. What is physical sense of inertia moment? What are the equations applied for determination of inertia moment of material point and rigid body?

6. Write Steiner’s theorem and explain its application.

7. Write formulas of basic dynamics law for translational and rotary movement.

8. Write the angular momentum conservation law.

9. Deduce the expression for calculation of inertia moment.

10. Deduce the expression for calculation of inertia moment determination error.

11. Formulate the main stages of laboratory work fulfillment.

12. Describe the laboratory experimental equipment for moment of inertia determination.

LABORATORY WORK

Kinematics and dynamics laws of translational
motion study using Atvud’s machine

The purpose of the work: to study the methods of kinematics and dynamics laws investigation using Atvud’s machine; to examine experimentally kinematics and dynamics laws of translational motion.

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Дата добавления: 2015-10-26