Answer:
Explanation:
given data
types of drinking straws
- square cross-sectional shape
- round shape
solution
we know that both perimeter of the cross section are equal
so we can say that
perimeter of square = perimeter of circle
4 × S = π × D
here S is length and D is diameter
S =
....................1
and
ratio of flow rate through the square and circle is here
Answer:
The transistor will be in amplifier mode and we will expect current will be higher than expected.
Answer:
By running multiple regression with dummy variables
Explanation:
A dummy variable is a variable that takes on the value 1 or 0. Dummy variables are also called binary
variables. Multiple regression expresses a dependent, or response, variable as a linear
function of two or more independent variables. The slope is the change in the response variable. Therefore, we have to run a multiple regression analysis when the variables are measured in the same measurement.The number of dummy variables you will need to capture a categorical variable
will be one less than the number of categories. When there is no obvious order to the categories or when there are three or more categories and differences between them are not all assumed to be equal, such variables need to be coded as dummy variables for inclusion into a regression model.
Answer:
1028.1184 Ohms
Explanation:
<u>Given the following data;</u>
- Initial resistance, Ro = 976 Ohms
- Initial temperature, T1 = 0°C
- Final temperature, T2 = 89°C
Assuming the temperature coefficient of resistance for carbon at 0°C is equal to 0.0006 per degree Celsius.
To find determine its new resistance, we would use the mathematical expression for linear resistivity;
![R_{89} = R_{0} + R_{0}(\alpha T)](https://tex.z-dn.net/?f=%20R_%7B89%7D%20%3D%20R_%7B0%7D%20%2B%20R_%7B0%7D%28%5Calpha%20T%29%20)
Substituting into the equation, we have;
![R_{89} = 976 + 976*(0.0006*89)](https://tex.z-dn.net/?f=%20R_%7B89%7D%20%3D%20976%20%2B%20976%2A%280.0006%2A89%29%20)
![R_{89} = 976 + 976*(0.0534)](https://tex.z-dn.net/?f=%20R_%7B89%7D%20%3D%20976%20%2B%20976%2A%280.0534%29%20)
![R_{89} = 976 + 52.1184](https://tex.z-dn.net/?f=%20R_%7B89%7D%20%3D%20976%20%2B%2052.1184%20)
![R_{89} = 1028.1184 \ Ohms](https://tex.z-dn.net/?f=%20R_%7B89%7D%20%3D%201028.1184%20%5C%20Ohms%20)
Answer:
a)σ₁ = 265.2 MPa
b)σ₂ = -172.8 MPa
c)![Stress\ ratio =-0.65](https://tex.z-dn.net/?f=Stress%5C%20ratio%20%3D-0.65)
d)Range = 438 MPa
Explanation:
Given that
Mean stress ,σm= 46.2 MPa
Stress amplitude ,σa= 219 MPa
Lets take
Maximum stress level = σ₁
Minimum stress level =σ₂
The mean stress given as
![\sigma_m=\dfrac{\sigma_1+\sigma_2}{2}](https://tex.z-dn.net/?f=%5Csigma_m%3D%5Cdfrac%7B%5Csigma_1%2B%5Csigma_2%7D%7B2%7D)
![2\sigma_m={\sigma_1+\sigma_2}](https://tex.z-dn.net/?f=2%5Csigma_m%3D%7B%5Csigma_1%2B%5Csigma_2%7D)
2 x 46.2 = σ₁ + σ₂
σ₁ + σ₂ = 92.4 MPa --------1
The amplitude stress given as
![\sigma_a=\dfrac{\sigma_1-\sigma_2}{2}](https://tex.z-dn.net/?f=%5Csigma_a%3D%5Cdfrac%7B%5Csigma_1-%5Csigma_2%7D%7B2%7D)
![2\sigma_a={\sigma_1-\sigma_2}](https://tex.z-dn.net/?f=2%5Csigma_a%3D%7B%5Csigma_1-%5Csigma_2%7D)
2 x 219 = σ₁ - σ₂
σ₁ - σ₂ = 438 MPa --------2
By adding the above equation
2 σ₁ = 530.4
σ₁ = 265.2 MPa
-σ₂ = 438 -265.2 MPa
σ₂ = -172.8 MPa
Stress ratio
![Stress\ ratio =\dfrac{\sigma_{min}}{\sigma_{max}}](https://tex.z-dn.net/?f=Stress%5C%20ratio%20%3D%5Cdfrac%7B%5Csigma_%7Bmin%7D%7D%7B%5Csigma_%7Bmax%7D%7D)
![Stress\ ratio =\dfrac{-172.8}{265.2}](https://tex.z-dn.net/?f=Stress%5C%20ratio%20%3D%5Cdfrac%7B-172.8%7D%7B265.2%7D)
![Stress\ ratio =-0.65](https://tex.z-dn.net/?f=Stress%5C%20ratio%20%3D-0.65)
Range = 265.2 MPa - ( -172.8 MPa)
Range = 438 MPa