What invention would you argue most impacted mechanical engineering
1 answer:
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Answer:
I am writing a Python function unique()
def unique(list): # function unique that takes a list as parameter
unique_list = [] #list to store unique elements
for elements in list: # loop that checks every element of the list
if elements not in unique_list: # takes unique elements from list
unique_list.append(elements)
#appends unique elements from list to unique_list
return unique_list #outputs unique_list elements
Explanation:
The unique() function takes a list as argument which is named as list.
unique_list is a new list which stores unique element from the list.
The loop moves through the elements of the list one by one.
if condition checks if the element in list is not present in the unique_list which means that element is unique to the unique_list.
If this condition is true this means that the element is not repeated and is not already present in unique_list. Then that element is included to the unique_list using append() function which appends an element into the unique_list from the list.
If you want to check if this function works you pass a list with repeated elements to this function so that it can print the unique elements as follows:
print(unique([1,2,2,2,2,3,4,4,4,4,4,5]))
Output:
[1, 2, 3, 4, 5]
The screen shot of the function along with its output is attached.
Answer:
Explanation:
In electrical terms, is the ratio of time in which a load or circuit is ON compared to the time in which the load or circuit is OFF.
The duty cycle or power cycle, is expressed as a percentage of the activation time. For example, a 70% duty cycle is a signal that 70% of the time is activated and the other 30% disabled. Its equation can be expressed as:
Where:
Here is a picture that will help you understand these concepts.
Answer:
12 mins
Explanation:
The summation of the forces in vertical direction
= Fb - Fd - w = 0 ∴ Fd = Fb - w ----- ( 1 )
Fb ( buoyant force ) = Pair * g * Vballoon ------- ( 2 )
Pair = air density , Vballoon = volume of balloon
Vballoon = , where D = 4 ∴ Vballoon = 33.51 ft^3
g = 32.2 ft/s^2
From property tables
Pair = 2.33 * 10^-3 slug/ft^3
μ ( dynamic viscosity ) = 3.8 * 10^-7 slug/ft.s
<em>Insert values into equation 2 </em>
Fb = ( 2.33 * 10^-3 ) * ( 32.2 ) *( 33.51 ) = 2.514 Ib
∴ Fd = 2.514 - 2.5 = 0.014 Ib ( equation 1 )
Assuming that flow is Laminar and RE < 1
Re = (Pair * vd) / μair -------- ( 3 )
where: Pair = 2.33 * 10^-3 slug/ft^3 , vd = ( 987 * 4 ) ft^2/s , μair = 3.8 * 10^-7 slug/ft.s
Insert values into equation 3
Re = 2.4 * 10^7 ( this means that the assumption above is wrong )
Hence we will use drag force law
Assume Cd = 0.5
Express Fd using the relation below
Fd = 1/2* Cd * Pair * AV^2
therefore V = 1.39 ft/s
Recalculate Reynold's number using v = 1.39 ft/s
Re = 34091
from the figure Cd ≈ 0.5 at Re = 34091
<u>Finally calculate the rise time ( time taken to reach an altitude of 1000 ft ) </u>
t = h/v
= 1000 / 1.39 = 719 seconds ≈ 12 mins
