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3 years ago

14. Low resistance combined with current flow is the description of a/an

Engineering

1 answer:

liubo4ka [24]3 years ago

3 0

I think b I’m for sure tho

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Supón que tienes que calcular el centro de gravedad de una pieza

Anton [14]

Answer:huh?

Explanation:

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4 years ago

Which of these physical concepts is most important in civil engineering? A. energy transformations B. motion under gravity C. he

melamori03 [73]

Answer:

energy transformations

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3 years ago

Here, we want to become proficient at changing units so that we can perform calculations as needed. The basic heat transfer equa

netineya [11]

Answer:

9500 kJ; 9000 Btu

Explanation:

Data:

m = 100 lb

T₁ = 25 °C

T₂ = 75 °C

Calculations:

1. Energy in kilojoules

ΔT = 75 °C - 25 °C = 50 °C = 50 K

$m = \text{100 lb} \times \dfrac{\text{1 kg}}{\text{2.205 lb}} \times \dfrac{\text{1000 g}}{\text{1 kg}}= 4.54 \times 10^{4}\text{ g}\\\\\begin{array}{rcl}q & = & mC_{\text{p}}\Delta T\\& = & 4.54 \times 10^{4}\text{ g} \times 4.18 \text{ J$\cdot$K$^{-1}$g$^{-1}$} \times 50 \text{ K}\\ & = & 9.5 \times 10^{6}\text{ J}\\ & = & \textbf{9500 kJ}\\\end{array}$

2. Energy in British thermal units

$\text{Energy} = \text{9500 kJ} \times \dfrac{\text{1 Btu}}{\text{1.055 kJ}} = \text{9000 Btu}$

7 0

4 years ago

Calculate the De-Broglie wavelength for electron accelerated across a potential of 10V, 100V, 1000V, and 10kV respectively. Whic

Arlecino [84]

Answer:

a) $\lambda=3.87 \r A$

b) $\lambda=1.23 \r A$

c) $\lambda=0.387 \r A$

d) $\lambda=0.123 \r A$

Explanation:

We know that the kinetic energy can be expressed in terms of momentum (p= mv):

$K=\frac{p^{2}}{2m}$

p is the momentum
m is the mass of the particle

So, the momentum will be:

$p=\sqrt{2mK}$ (1)

We can use the energy conservation to relate K and the electric potential energy. We assume that all potential energy becomes kinetic energy. Therefore:

$K=q_{e}V$ (2)

a) If V=10 [V], K will be:

$K=1.6*10^{-19}*10=1.6*10^{-18}[J]$

We can find the momentum using the equation (1)

$p=\sqrt{2*9.1 x 10^{-31}*1.6*10^{-18}}=1.71*10^{-24}[kg*m*s^{-1}]$

The De-Broglie wavelength equation is given by:

$\lambda=\frac{h}{p}$ (3)

h is the Plank constant ( $h=6.626 x 10^{-34} [J*s]$ )

$\lambda=\frac{6.626 x 10^{-34}}{1.71*10^{-24}}=3.87*10^{-10}[m]=3.87 \r A$

b) If V=100 [V], using the same analyze, the De-Broglie wavelength will be:

$K=1.6*10^{-19}*100=1.6*10^{-17}[J]$

$p=\sqrt{2*9.1 x 10^{-31}*1.6*10^{-17}}=5.39*10^{-24}[kg*m*s^{-1}]$

$\lambda=\frac{6.626 x 10^{-34}}{5.39*10^{-24}}=1.23*10^{-10}[m]=1.23 \r A$

c) V=1000 [V]

$K=1.6*10^{-19}*100=1.6*10^{-16}[J]$

$p=\sqrt{2*9.1 x 10^{-31}*1.6*10^{-16}}=1.71*10^{-23}[kg*m*s^{-1}]$

$\lambda=\frac{6.626 x 10^{-34}}{1.71*10^{-23}}=3.87*10^{-11}[m]=0.387 \r A$

d) V=10000 [V]

$K=1.6*10^{-19}*100=1.6*10^{-15}[J]$

$p=\sqrt{2*9.1 x 10^{-31}*1.6*10^{-15}}=5.40*10^{-23}[kg*m*s^{-1}]$

$\lambda=\frac{6.626 x 10^{-34}}{5.40*10^{-23}}=1.23*10^{-11}[m]=0.123 \r A$

The fringe spacing interference is proportional to the wavelength, so in our case, the larger fringe spacing occurs when voltage is 10 V, here λ = 3.87 angstroms.

I hope it helps you!

5 0

3 years ago

John has two identical water barrels in his backyard. One day during the self-isolation period, he gets bored and rigs up a shor

Natali [406]

Answer:

The barrel with the sharp edge will drain faster.

Explanation:

The barrel with filed down entrance will gradually allow water to flow out due to the soft round corner.

However, the barrel with sharp edge will create turbulent eddies because of the sudden contraction phenomenon at the exit point. This turbulent eddies will occur in the inside portion of the sharp edge. First, let us understand what Eddies are.

An eddy, is fluid current whose flow direction differs from that of the general flow. Eddies can transfer much more energy and dissolved matter within the fluid and they actually mix together large masses of fluid. They generally become more numerous as the fluid flow velocity increases.

Based on the above definition, we can see that due to the sharp edge created, the flow direction differs from that of the general flow thereby creating eddies that are usually turbulent which causes more outflow of water than that with the soft edge.

5 0

3 years ago