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3 years ago

12

There are four spheres of earth. These include ______, _, and _____. They are important because when th

ey work together they help keep plants and animals alive on earth.

1 answer:

ololo11 [35]3 years ago

4 0

Answer:

"lithosphere" , "hydrosphere" , "biosphere" , "atmosphere"

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A heat recovery device involves transferring energy from the hot flue gases passing through an annular region to pressurized wat

Elina [12.6K]

Answer:

See explaination

Explanation:

Please kindly check attachment for the step by step solution of the given problem.

4 0

3 years ago

A square loop of wire surrounds a solenoid. The side of the square is 0.1 m, while the radius of the solenoid is 0.025 m. The sq

Semmy [17]

Answer:

I=9.6×e^{-8} A

Explanation:

The magnetic field inside the solenoid.

B=I*500*muy0/0.3=2.1×e ^-3×I.

so the total flux go through the square loop.

B×π×r^2=I×2.1×e^-3π×0.025^2

=4.11×e^-6×I

we have that

(flux)'= -U

so differentiating flux we get

so the inducted emf in the loop.

U=4.11×e^{-6}×dI/dt=4.11×e^-6×0.7=2.9×e^-6 (V)

so, I=2.9×e^{-6}÷30

I=9.6×e^{-8} A

6 0

3 years ago

Air flows at 45m/s through a right angle pipe bend with a constant diameter of 2cm. What is the overall force required to keep t

HACTEHA [7]

Answer:

b)1.08 N

Explanation:

Given that

velocity of air V= 45 m/s

Diameter of pipe = 2 cm

Force exerted by fluid F

$F=\rho AV^2$

So force exerted in x-direction

$F_x=\rho AV^2$

$F_x=1.2\times \dfrac{\pi}{4}\times 0.02^2\times 45^2$

F=0.763 N

So force exerted in y-direction

$F_y=\rho AV^2$

$F_y=1.2\times \dfrac{\pi}{4}\times 0.02^2\times 45^2$

F=0.763 N

So the resultant force R

$R=\sqrt{F_x^2+F_y^2}$

$R=\sqrt{0.763^2+0.763^2}$

R=1.079

So the force required to hold the pipe is 1.08 N.

3 0

3 years ago

Which crystal system(s) listed below has (have) the following relationship for the unit cell edge lengths?

lianna [129]

Answer:

Both B and G ( Hexagonal and Tetragonal )

Explanation:

The crystals system listed below has the following relationship for the unit cell edge lengths; a = b ≠ c ( hexagonal and Tetragonal )

hexagonal ; represents a crystal system which has three equal axes that have an angle of 60⁰ between them while Tetragonal denotes crystals that have three axes which have only two of its axes equal in length.

5 0

3 years ago

Consider casting a concrete driveway 40 feet long, 12 feet wide and 6 in. thick. The proportions of the mix by weight are given

Akimi4 [234]

Answer:

Weight of cement = 10968 lb

Weight of sand = 18105.9 lb

Weight of gravel = 28203.55 lb

Weight of water = 5484 lb

Explanation:

Given:

Entrained air = 7.5%

Length, L = 40 ft

Width,w = 12 ft

thickness,b= 6 inch, convert to ft = 6/12 = 0.5 ft

Specific gravity of sand = 2.60

Specific gravity of gravel = 2.70

The volume will be:

40 * 12 * 0.5 = 240 ft³

We need to find the dry volume of concrete.

Dry volume = wet volume * 1.54 (concrete)

Dry volume will be = 240 * 1.54 = 360ft³

Due to the 7% entarained air content, the required volume will be:

V = 360 * (1 - 0.07)

V = 334.8 ft³

At a ratio of 1:2:3 for cement, sand, and gravel respectively, we have:

Total of ratio = 1+2+3 = 6

Their respective volume will be =

Volume of cement = $\frac{1}{6}*334.8 = 55.8 ft^3$

Volume of sand = $\frac{2}{6}*334.8 = 111.6 ft^3$

Volume of gravel = $\frac{3}{6}*334.8 = 167.4 ft^3$

To find the pounds needed the driveway, we have:

Weight = volume *specific gravity * density of water

Specific gravity of cement = 3.15

Weight of cement =

55.8 * 3.15 * 62.4 = 10968 pounds

Weight of sand =

111.6 * 2.60 * 62.4 = 18105.9 lb

Weight of gravel =

167.4 * 2.7 * 62.4 = 28203.55 lb

Given water to cement ratio of 0.50

Weight of water = 0.5 of weight of cement

= 1/2 * 10968 = 5484 lb

4 0

4 years ago