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3 years ago

How old are legos? Who created them? Why did they create them?

1 answer:

4 0

“How old are the legos” 89 years old.

“Who created them?” Ole Kirk Christiansen.

“Why did they created them?” As a you man, Christiansen turned his love of whittling and playing with wood into a Business and, in 1916, he opened his own shop. Since times were so hard, Christiansen made the hard decision to use his wood to create inexpensive goods that might actually sell. Among them were Cheap toys.

Hope this helps•

Bye~

•Kate•

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A 150 MVA, 24 kV, 123% three-phase synchronous generator supplies a large network. The network voltage is 27 kV. The phase angle

Aleks04 [339]

Answer:

the generator induced voltage is 60.59 kV

Explanation:

Given:

S = 150 MVA

Vline = 24 kV = 24000 V

$X_{s} =1.23(\frac{V_{line}^{2} }{s} )=1.23\frac{24000^{2} }{1500} =4723.2 ohms$

the network voltage phase is

$V_{phase} =\frac{V_{nline} }{\sqrt{3} } =\frac{27}{\sqrt{3} } =15.58kV$

the power transmitted is equal to:

$|E|=\frac{P*X_{s} }{3*|V_{phase}|sinO } ;if-O=60\\|E|=\frac{300*4.723}{3*15.58*sin60} =34.98kV$

the line induced voltage is

$|E_{line} |=\sqrt{3} *|E|=\sqrt{3} *34.98=60.59kV$

7 0

3 years ago

Calculate the wire pressure for a round copper bar with an original cross-sectional area of 12.56 mm2 to a 30% reduction of area

dybincka [34]

Answer:153.76 MPa

Explanation:

$Initial Area\left ( A_0\right )=12.56 mm^2$

$Final Area\left ( A_f\right )=0.7\times 12.56 mm^2=8.792 mm^2$

$Die angle=30^{\circ}$

$\alpha =\frac{30}{2}=15^{\circ}$

$\mu =0.08$

$Yield stress\left ( \sigma _y \right )=350 MPa$

$B=\mu cot\left ( \aplha\right )=0.2985$

$\sigma _{pressure}=\sigma _y\left [\frac{1+B}{B}\right ]\left [ 1-\frac{A_f}{A_0}\right ]^B$

$\sigma _{pressure}=350\left [\frac{1+0.2985}{0.2985}\right ]\left [ 1-\frac{8.792}{12.56}\right ]^{0.2985}$

$\sigma _{pressure}=153.76 MPa$

8 0

3 years ago

A cone-shaped part is to be fabricated using stereolithography. The radius of the cone at its base = 35 mm, and its height = 50

iren [92.7K]

Explanation:

volume = πR²h/3

= πx35²x50/3

= 192325/3

= 64166.725

number of layers n = 50mm/0.05

n = 1000layers

average volume = 64166.725/1000

= 64.167mm³

average area = 64.167/0.05

= 1283.34mm²

average time = 1283.34/900mm x 0.22

= 6.48

6.48 + 15 seconds

= 21.48 seconds

time required = 1000x21.48

= 21480 seconds

convert to minutes

21480/60

= 358 minutes

21480/3600

= 5.967 hours

8 0

3 years ago

Given the following access-control list: access-list 90 deny 10.168.7.0 0.0.0.255 access-list 90 permit host 10.168.7.10 access-

Yuri [45]

Answer:

D. Both hosts 10.168.7.10 and 10.168.7.11 will be permitted

Explanation:

access-list 90

deny 10.168.7.0 0.0.0.255

permit 10.168.7.10

permit 10.168.7.11

permit 10.168.7.12

deny any

7 0

3 years ago

Use phasor techniques to determine the impedance seen by the source given that R = 4 Ω, C = 12 μF, L = 6 mH and ω = 2000 rad/sec

Zielflug [23.3K]

Answer:

Z = 29.938Ω ∠22.04°

I = 2.494A

Explanation:

Impedance Z is defined as the total opposition to the flow of current in an AC circuit. In an R-L-C AC circuit, Impedance is expressed as shown:

Z² = R²+(Xl-Xc)²

Z = √R²+(Xl-Xc)²

R is the resistance = 4Ω

Xl is the inductive reactance = ωL

Xc is the capacitive reactance =

1/ωc

Given C = 12 μF, L = 6 mH and ω = 2000 rad/sec

Xl = 2000×6×10^-3

Xl = 12Ω

Xc = 1/2000×12×10^-6

Xc = 1/24000×10^-6

Xc = 1/0.024

Xc = 41.67Ω

Z = √4²+(12-41.67)²

Z = √16+880.31

Z = √896.31

Z = 29.938Ω (to 3dp)

θ = tan^-1(Xl-Xc)/R

θ = tan^-1(12-41.67)/12

θ = tan^-1(-29.67)/12

θ = tan^-1 -2.47

θ = -67.96°

θ = 90-67.96

θ = 22.04° (to 2dp)

To determine the current, we will use the relationship

V = IZ

I =V/Z

Given V = 12V

I = 29.93/12

I = 2.494A (3dp)

7 0

3 years ago