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3 years ago

What was J.J Thompson working on when we discovered the electron?

1 answer:

7 0

J.J. Thomson used a cathode ray tube to discover the electron. Cathode ray tubes are vacuum tubes that contain two electrodes - one on each side. One of the electrodes (the cathode) fires electrons at the other (the anode) when voltage is added to the system.

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A pin fin of uniform, cross-sectional area is fabricated of an aluminum alloy (k = 160 W/m-K). The fin diameter is D = 4 mm, and

frozen [14]

Answer:

Given that

D= 4 mm

K = 160 W/m-K

h=h = 220 W/m²-K

ηf = 0.65

We know that

$m=\sqrt{\dfrac{hP}{KA}}$

For circular fin

$m=\sqrt{\dfrac{4h}{KD}}$

$m=\sqrt{\dfrac{4\times 220}{160\times 0.004}}$

m = 37.08

$\eta_f=\dfrac{tanhmL}{mL}$

$0.65=\dfrac{tanh37.08L}{37.08L}$

By solving above equation we get

L= 36.18 mm

The effectiveness for circular fin given as

$\varepsilon =\dfrac{2\ tanhmL}{\sqrt{\dfrac{hD}{K}}}$

$\varepsilon =\dfrac{2\ tanh(37.08\times 0.03618)}{\sqrt{\dfrac{220\times 0.004}{160}}}$

ε = 23.52

5 0

3 years ago

Read 2 more answers

What are some examples of aerobic exercise?

Firdavs [7]

Answer:

swimming, cycling, and jogging

Explanation:

4 0

3 years ago

A house brick has a volume of 1900 cm³ and a weight in air of 80N.What is its apparent weight in water?The density of water is 1

Shtirlitz [24]

Answer:

61 N

Explanation:

We'll begin by calculating the mass of the brick when placed in water. This can be obtained as follow:

Volume of brick = 1900 cm³

Density of water = 1 g/cm³

Mass of brick in water =…?

Density = mass / volume

1 = mass of brick in water / 1900

Cross multiply

Mass of brick in water = 1 × 1900

Mass of brick in water = 1900 g

Next, we shall convert 1900 g to Kg.

1000 g = 1 Kg

Therefore,

1900 g = 1900 g × 1 Kg / 1000 g

1900 g = 1.9 Kg

Next, we shall determine the weight in water. This can be obtained as follow:

Mass (m) = 1.9 Kg

Acceleration due to gravity (g) = 10 m/s²

Weight (W) =?

W = m × g

W = 1.9 × 10

W = 19 N

Thus, the weight of the brick in water is 19 N.

Finally, we shall determine the apparent weight of the brick in water. This can be obtained as follow:

Weight in air = 80 N

Weight in water = 19 N

Apparent weight =?

Apparent weight = weight in air – weight in water

Apparent weight = 80 – 19

Apparent weight = 61 N

3 0

3 years ago

What must be the pressure difference between the two ends of a 2.6 km section of pipe, 36 cm in diameter, if it is to transport

ad-work [718]

Answer: $1.13(10)^{3} Pa$

Explanation:

This problem can be solved by the following equation:

$\Delta P=\frac{8 \eta L Q}{\pi r^{4}}$

Where:

$\Delta P$ is the pressure difference between the two ends of the pipe

$\eta=0.20 Pa.s$ is the viscosity of oil

$L=2.6 km=2600 m$ is the length of the pipe

$Q=900 \frac{cm^{3}}{s} \frac{1 m^{3}}{(100 cm)^{3}}=0.0009 \frac{m^{3}}{s}$ is the Rate of flow of the fluid

$d=36 cm=0.36 m$ is the diameter of the pipe

$r=\frac{d}{2}=0.18 m$ is the radius of the pipe

Soving for $\Delta P$ :

$\Delta P=\frac{8 (0.20 Pa.s)(2600 m)(0.0009 \frac{m^{3}}{s})}{\pi (0.18 m)^{4}}$

Finally:

$\Delta P=1135.26 Pa \approx 1.13(10)^{3} Pa$

7 0

3 years ago

Which of the following items has the most inertia while at rest?

netineya [11]

Answer:

airplane

Explanation:

as greater mass greater inertia

8 0

3 years ago