Circular Motion rubber stopper lab

In summary, the conversation discusses a circular motion lab in which a rubber stopper and mass are spun on a string to calculate the period. Three different graphs are used to analyze the relationship between force, radius, and mass with period. The equations of the lines are given in terms of T and the final equation is needed to relate Fc, m, r, and T. The first part has already been completed, and the second part involves recognizing that the constants in each equation may depend on the other variables.
  • #1
g4orce
I have a circular motion lab, in which we spin a rubber stopper attached at one end and a mass at the other end of a string. We calculate the period by the recording the time it takes for 20 revolutions. And we figure out the force Fc.

So we do three different graphs:

one for Fc vs Period
2nd for Radius vs Period
3rd for Mass vs Period


And we get the following eqn's of the line once, notice I have subsituted for x and y from the above variables.

Fc = 3.0381/T^2 - 2.6566
R=1.5962T^2 - 0.0778
m= 0.1031T^2 - 0.0024

The problems is that I have to Write each eqn in terms of T (period) and then write One final eqn that relates Fc, m, r and T. How do i do this?
 
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  • #2
The first one, "Write each eqn in terms of T" you've already done. The equations you give ARE in terms of T.

Tp do the second one, recognize that what you are saying is that the constants in each equation must depend on the other variables (you don't say it but I assume that each graph was gotten by holding the other variables constant). The crucial point is that R (minus a constant that MIGHT depend on m) and m (minus a constant that MIGHT depend on R) are both proportional to T^2 while F is proportional to 1/T^2.
 
  • #3


To write each equation in terms of T, you can simply substitute the value of T from the second equation into the first and third equations. This will give you:

Fc = 3.0381/(1.5962T^2 - 0.0778)^2 - 2.6566
m = 0.1031/(1.5962T^2 - 0.0778)^2 - 0.0024

To write one final equation that relates Fc, m, r, and T, you can use the equation for centripetal force, Fc = mω^2r, where ω is the angular velocity. Since we know that ω = 2π/T, we can substitute this into the equation to get:

Fc = (m(2π/T)^2)r

This equation relates all the variables in terms of T, as requested.
 

1. What is the purpose of the Circular Motion rubber stopper lab?

The purpose of this lab is to investigate the relationship between centripetal force, mass, velocity, and radius in circular motion. This can help demonstrate the concept of centripetal force and its effects on an object in circular motion.

2. What materials are needed for the Circular Motion rubber stopper lab?

The materials needed for this lab typically include a rubber stopper, string, a ruler, a stopwatch, and a weight hanger with various masses. Some labs may also require a protractor or a motion sensor.

3. How is the Circular Motion rubber stopper lab set up?

The rubber stopper is tied to one end of the string and the other end is attached to the weight hanger. The string is then passed through a hole in the center of the ruler, which is held horizontally. The weight hanger is then hung off the edge of the table and the rubber stopper is swung in a horizontal circle.

4. What are the variables being tested in the Circular Motion rubber stopper lab?

The variables being tested in this lab include the mass of the rubber stopper, the velocity of the rubber stopper, and the radius of the circular motion. The centripetal force acting on the rubber stopper is also a calculated variable in this lab.

5. What are some possible sources of error in the Circular Motion rubber stopper lab?

Some sources of error in this lab may include friction between the string and the ruler, air resistance on the rubber stopper, and human error in measuring the variables. It is important to repeat the experiment multiple times and take an average to minimize these errors.

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