help me with physics

[F.B]

Sorry is its really hard to read the chart but i dont know how to fix it. Anyways there are 4 different lengths and at each length the resistance gets stronger and stronger. i guess i'll write a little about the chart. The first column is Diameter the numbers are 0.025, 0.04, 0.075, 0.125. The next columns are resistance differing between length. The first column of length is 100 and the resistances are 15.7, 6.1, 1.9 and 0.6. The next length is 140 and the resistances are 22, 8.5, 2.5, 0.9. The next length is 170, the resistances are 26.8, 10.4, 3, 1.1. The final column of length is 220 and the resistances are 34.7, 13.3, 3.9, 1.4. I hope that helps. Anyways my question is that i have to create a proportionality statement between the length diameter and resistance and a function statement. So can anyone please help me.

 

Length 100 140 170 220

Diameter (cm) Resistance

0.025 15.7 22.0 26.8 34.7

0.04 6.1 8.5 10.4 13.3

0.075 1.9 2.5 3.0 3.9

0.125 0.6 0.9 1.1 1.4

[mezarashi]

Proportionality statement I see? This can be the easiest thing to do given any set of correlated data. I'm guessing maybe you don't fully understand what it means. They are basically asking you for the relationship between Length, Diameter, and Resistance.

 

Take a look at your data. There are three variables. With one variable kept constant, increasing the second variable, how does the third variable change? Some hints, variables can be:

 

- proportional to each other (momentum and velocity)

- inversely proportional to each other (pressure and volume in ideal gases)

- proportional to the square (kinetic energy and velocity)

- inversely proportional to the square (gravitational force and distance between the masses)

[F.B]

I know what a proportionality statement is lol and i know how to make them. For that data R is proportional to 1/d^2 but my problem is coming up with a statement relating the resistance, length and diameter. So I was wondering if you could help me come up with this.

[mezarashi]

Can you define what "statement" means? Unless I am misunderstanding you, I would believe you are looking for:

 

R is proportional to L/d^2 ?

 

which can be induced logically since we know that

R is proportional to L

L proportional to d^2

and R is proportional to 1/d^2

 

Your empirical equation would then be:

 

R = kL/d^2, where k is some constant of proportionality.

[F.B]

By statement i mean function. Oh and you wrote R is proportional to L/d^2. If i use that that i dont get resistance. Also R = kL/d^2, whats k supposed to be i cant find the slope of everything combined so what number am i supposed to use because on another question i have to use that equation to determine R from these numbers that they give me.

[mezarashi]

By statement i mean function. Oh and you wrote R is proportional to L/d^2. If i use that that i dont get resistance.

 

You have 3 variables and you have the three variables in an equation. What's wrong with it? You don't get resistance? But resistance is in the equation no? Elaborate.

 

Also R = kL/d^2, whats k supposed to be i cant find the slope of everything combined so what number am i supposed to use because on another question i have to use that equation to determine R from these numbers that they give me.

 

To solve for the proportionality constant, you would plug in the values of R, L, and d for a particular data point and solve for k. Given that your data is not perfect, your value for k will probably vary depending on the point that you use.