Part 1: Feather constant

Part 1 of the laboratory session, which is divided into subtasks 1 and 2, is about determining the spring constant for a spring in two different ways. The main purpose of part 1 of the laboratory session is to give you increased confidence in models that describe swing movements. Part 1 also provides the opportunity to train yourself in recording and processing measurement data.

Material

Subtasks 1 are based on the filmhttp://youtu.be/18g4GfWmy5Y (Spring extension - mass) and subtask 2 on the filmhttp://youtu.be/pzQkfnZ6MvU (Spring swing, time - mass).

Assessment and accounting

Accounting for this laboratory work is done by entering measurement values and calculated values in tables and graphs and writing down calculations and answers to each task directly in this document that you then submit. The questions are answered briefly. Part 2 provides an opportunity to comment on results to a greater extent.

Data

1: To use extension in determining the spring constant k

Imagine that you and a fellow laboratory are going to investigate how the spring extension is affected when hanging different weights on the spring. You have followed the steps in the method below. The medlaborant performs the laboratory work practically, watch the filmhttp://youtu.be/18g4GfWmy5Y (Spring extension - mass) and you make readings, create tables, perform calculations and create diagrams.

1. Try to find a place where you can hang up the feather.
2. Hang the lightest weight in the feather.
3. Draw up a table in which you enter the mass of the weights m (kg), calculate the spring force F_f (N) (how then?) and enter this into the table, as well as the spring extension s (m).
4. Hang a few different weights in the spring and enter your values and calculations in the table according to the previous point.
5. Starting from your table, draw a diagram using the spring force F_f (N) as a function of the spring extension s (m) (i.e. the spring force on the y-axis and the spring extension on the x-axis).
6. Hopefully it's clear that a line can be aligned with the points. We are interested in the slope of the line describing how the spring force and spring elongation depend on each other. The value of the slope of the line is a close value of the spring constant k. Using your knowledge of mathematics and your diagram, you should figure out k.

What value did you get on the feather constant and what device does it have?

Also present the table, charts and calculations.

Answer:

2: Using the oscillation time in determining the spring constant k

This task is similar to the previous task in that you are going to investigate a relationship between two quantities, the oscillation time T (s) and the mass m (kg). Here, too, you should draw up a table and draw a diagram. Readings are also made here via a film:

http://youtu.be/pzQkfnZ6MvU (Spring swing, time - mass).

Part 2: Pendulum

Part 2 of the laboratory session, which is divided into subtasks 3, 4 and 5. In subtask 3, the importance of mass for the oscillation time of a pendulum is investigated and in subtask 4 pendulum motions are used to experimentally determine a value of the acceleration of gravity g.

The purpose of part 2 of the laboratory session is for the student to gain a deeper understanding of models that describe oscillation movements. Part 2 also provides the opportunity to train yourself in experimenting and processing measurement data.

Preparation

Part 2: Pendulum uses methods and is to some extent based on what you have done in part 1 of the laboratory session. Therefore, first finish part 1 before you begin.

Material

You are going to experiment yourself and this means that you need to create a pendulum and perform measurements. The following materials are needed.

1. A thin string or sewing thread at least 1 m long.
2. Different weights or objects with different mass that can be hung in the pendulum, such as trays or rings.
3. A clock to measure time with, such as http://www.tidtagare.se/.
4. A ruler, thumbstick or tape measure.
5. A scale, such as a kitchen scale. One option is to weigh on the fruit or candy scales in the nearest grocery store.

Assessment and accounting

This laboratory session is presented by describing the method, material and layouts in this document. You also enter metrics and calculated values in tables and charts and write down calculations and responses to each task directly in this document that you then submit. The assessment of the laboratory session is based on the chosen methods and how detailed the reports are to the assignments.

3: The relationship between oscillation time and mass of a pendulum

A table showing how the oscillation time T (s) varies with the mass m (kg) should be drawn up.

1. Attach the string, about long, to e.g. a door frame.1 m
2. For different weights that you hang from the string, you let the pendulum swing. Do not let the pendulum swing too far, but use relatively small tee angles. For each of these weights, with a stopwatch you should measure the time of 10 full oscillations. Why not just measure the time of a swing?
3. Establish a table in which, for each weight, you report the time for 10 oscillations (=10T) and the time for one oscillation (T (s)).

Explain how the pendulum was created and how measurements were performed, present your table, draw conclusions and comment on the result.

Answer:

3: The relationship between oscillation time and mass of a pendulum

A table showing how the oscillation time T (s) varies with the mass m (kg) should be drawn up.

1. Attach the string, about long, to e.g. a door frame.1 m
2. For different weights that you hang from the string, you let the pendulum swing. Do not let the pendulum swing too far, but use relatively small tee angles. For each of these weights, with a stopwatch you should measure the time of 10 full oscillations. Why not just measure the time of a swing?
3. Establish a table in which, for each weight, you report the time for 10 oscillations (=10T) and the time for one oscillation (T (s)).

Explain how the pendulum was created and how measurements were performed, present your table, draw conclusions and comment on the result.

Answer:

4: The relationship between swing time and the length of a pendulum

1. Attach the string to, for example, a door frame and hang any weight in the string.
2. Vary the pendulum length, that is, the length of the string, and take the time for 10 full swings for each length of the string.
3. Draw up a table in which you enter the pendulum length l (m), the time of 10 oscillations 10 T (s), the time of a oscillation T (s), and the time of a oscillation squareD² (p²).
4. Starting from the values in the table, draw a diagram with the oscillation time squareD² (s²) as a function of the pendulum length l (m). That is, the swing time squared on the y-axis and the length of the x-axis.
5. Hopefully, the points on the chart are almost on one line. If a line is adapted to the points, the slope of the line can be used to calculate a close value of the acceleration of gravity g. This is realized by writing about the connection