Lab Project - build a physical pendulum with the smallest period

In summary, the conversation discusses the design and setup of a physical pendulum for a lab project with the goal of achieving the smallest possible period. The components used include a metal tube, metal collar, two TT spools, a white TT rod, and a 10-gram disk mounted on a rotary motion sensor. The angular displacement of the rod must not exceed 10 degrees from its natural resting position. The group is stuck on how to set up the mathematical expression for determining the minimum period and is considering different inertia equations for the different components involved. They are seeking advice on how to approach the problem and are questioning the correctness of their current equations.
  • #1
cvali
1
0
Hi, I'm a student working with my group to create a lab for our final lab project. Me and my teammates are stuck on how we should begin to set up the project. I attached 4 photos, one of the pendulum setup, one of the model of our pendulum setup, and two others of the lab sheet guide.

The purpose of the lab project is to design and build a physical pendulum with the smallest possible period. The physical pendulum must be built of the supplied metal tube, metal collar, two TT spools, white TT rod, and 10-gram disk. It must be mounted on the supplied rotary motion sensor using the encoder's largest radius pulley. The angular displacement of the rod from its natural resting position must never be more than 10 degrees.
In the pendulum setup (referring to the model), the only thing we can manipulate is the TT spools/rod and Metal collar, everything else must stay the same.

In terms of the first section of the project, image IMAG0075. we were thinking the following with respect to the chart (though this can be altered if necessary):

1) Neglect
2) Solid Cylinder
3) Annular Cylinder
4) Annular Cylinder
5) Solid Cylinder
6) Annular Cylinder

We're stuck on the setup of the mathematical expression we are to derive to solve for Tminimum from the information given. We must include the pendulums period (Ttheory) in terms of d1 and d2 (d1 and d2 being distances from the rods axis of rotation to the center of the mass of the TT spool and the center of mass of the metal collar).

We believe we should be using the following (inertia) equations in respect to image IMAG0075

1) n/a
2) (1/12)ML^2
3) MR^2
4) MR^2
5) (1/12)ML^2
6) MR^2

We're not sure if we are on the right track. Any advice on how we should approach this would be awesome, or an explanation on how we should put the formulas together to attain the lowest period in which the lowest point of the pendulum swings.


Homework Statement





2. Relevant

The Attempt at a Solution

 

Attachments

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  • #2
The equation for MoI of annular cylinder cannot be correct. There are two radii involved, it only has one.

The TT rod, one TT spool and the disk are located differently than other cylinders, so you must have different equations for them.
 

1. How do I build a physical pendulum for this lab project?

To build a physical pendulum, you will need a rigid rod or string, a weight or mass to act as the pendulum bob, and a pivot point. The length of the pendulum should be at least 10 times longer than the diameter of the pendulum bob. You can use materials such as a ruler, a paper clip, and a pencil to construct the pendulum. Follow the instructions provided in the lab project guidelines for specific measurements and assembly.

2. What is the smallest period for a physical pendulum?

The period of a physical pendulum is dependent on its length, mass, and the acceleration due to gravity. The smallest period for a physical pendulum will be achieved when the length of the pendulum is at its minimum, and the mass is at its maximum. However, it is important to note that the period cannot be smaller than the smallest unit of time, which is one Planck time (5.39 x 10^-44 seconds).

3. How do I calculate the period of a physical pendulum?

The period of a physical pendulum can be calculated using the formula T = 2π√(I/mgh), where T is the period, I is the moment of inertia, m is the mass of the pendulum, g is the acceleration due to gravity, and h is the distance between the pivot point and the center of mass of the pendulum. Make sure to use consistent units when plugging in values to the formula.

4. What factors can affect the period of a physical pendulum?

The period of a physical pendulum can be affected by the length of the pendulum, the mass of the pendulum bob, the pivot point, and the acceleration due to gravity. Other factors such as air resistance, friction, and the amplitude of the pendulum's swing can also have an impact on the period.

5. Can I make any modifications to the physical pendulum to decrease the period?

Yes, you can make modifications to the physical pendulum to decrease the period. Some possible modifications include decreasing the length of the pendulum, increasing the mass of the pendulum bob, and changing the pivot point. However, keep in mind that the period cannot be smaller than one Planck time, as mentioned in the answer to the second question.

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