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BlackZzzverrR [31]

3 years ago

13

Which of the following has led to a safer and more prosperous global community within the last century? the Bronze Age composite

materials new materials ceramics

2 answers:

sattari [20]3 years ago

4 0

Answer:

The bronze age

musickatia [10]3 years ago

4 0

Answer:

C.

Explanation:

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Between chain, belt and gear drive, which causes more friction?

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All of them cause friction

Explanation:

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2 years ago

What is the reason that the work of engineer who studies earthquakes, landslides, and rock falls is valuable to the petroleum in

eduard

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D

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1 year ago

Water that has evaporated returns to earth as

denis23 [38]

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rain

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2 years ago

Read 2 more answers

A 8.0-m-diameter parachute of a new design is to be used to transport a load from flight altitude to the ground with an average

S_A_V [24]

Answer:

drag coefficient for the parachute is Cd = 1.84177

Explanation:

given data

diameter = 8.0 m

average vertical speed = 3 m/s

total weight of load = 200 N

to find out

drag coefficient for the parachute

solution

we will apply here drag coefficient formula that is express as here

drag coefficient Cd = $\frac{2w}{\rho v^2A}$ ......................1

here w is total load and A is area and v is speed

and here ρ = 1.22 kg/cu

put here value we get

Cd = $\frac{2*4*200}{1.229*5^2*\pi * 3^2}$

Cd = 1.84177

drag coefficient for the parachute is Cd = 1.84177

3 0

2 years ago

When a man returns to his well-sealed house on a summer day, he finds that the house is at 35°C. He turns on the air conditioner

ipn [44]

Answer:

$\dot W = 1.667\, kW$

Explanation:

A well-sealed house means that there is no mass interaction between air indoors and outdoors. Hence, cooling process is isochoric. The heat removed by the air conditioner is:

$\dot Q_{L} = \frac{m_{air}}{\Delta t} \cdot c_{v, air} \cdot (T_{o}-T_{f})\\\dot Q_{L} = \frac{800\, kg}{(30\, min)\cdot (\frac{60\, s}{1 \, min} )}\cdot (0.7 \frac{kJ}{kg \cdot K}) \cdot (15\, K)\\\dot Q_{L} = 4.667\, kW$

The power drawn by the air conditioner is:

$\dot W = \frac{\dot Q_{L}}{COP_{R}} \\\dot W = \frac {4.667\, kW}{2.8}\\\dot W = 1.667\, kW$

3 0

2 years ago