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3 years ago

What is the biggest challenge for space travel

1 answer:

8 0

The biggest challenge for them Radiation. The first hazard of a human mission to Mars is also the most difficult to visualize because, well, space radiation is invisible to the human eye and Isolation and confinement.

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I am standing on the upper deck of the football stadium. I have an egg in my hand. I am going to drop it and you are going to tr

Alina [70]

Answer:

Δx = 25 ft.

Explanation:

Assuming that the person on the ground starts running at the same time as the egg is dropped, we have two simultaneous trajectories:

1 ) Egg falling:

If the egg is dropped, and we neglect the air resistance, we can use the kinematic equation that relates the distance and fall time, as follows:

yf-y₀ = 1/2* g* t²

If we take the up direction as positive, we can solve for t as follows:

0-100 ft = 1/2* (-32.15 ft/s²)* t²

⇒ t = $\sqrt{(100*2)/32.15}$ = 2.5 sec.

2) Person on the ground running away:

In order to be able to run away, and then return to catch the egg, running at constant speed, he must run during exactly the half of the time that the egg is falling, i.e., 1.25 sec.

We can get the distance at which he can reach, applying the definition of velocity:

v = (xf-x₀) / (tfi-t₀)

If we choose t₀=0 and x₀ = 0 , we can solve for xf, as follows:

xf = v*t = 20 ft/sec*1.25 sec = 25 ft.

8 0

3 years ago

A Carnot heat engine absorbs 235 KW of heat from a heat source and rejects 164 KW to the atmosphere. Determine the thermal effic

nevsk [136]

Answer:

43.2%

Explanation:

Given that,

Heat absorbed by a carnot heat engine, $Q_1=235\ kW$

Heat rejected to the atmosphere, $Q_2=164\ kW$

We need ti find the thermal efficiency of the heat engine. It is equal to the ratio of output work to the energy supplied. Its mathematical form is given by :

$\eta=1-\dfrac{Q_1}{Q_2}\\\\\eta=1-\dfrac{235}{164}\\\\\eta=-0.432$

$\eta=-43.2\%$

The egative value of efficiency shows work is done by the engine.

5 0

3 years ago

Water is flowing in a metal pipe. The pipe OD (outside diameter) is 61 cm. The pipe length is 120 m. The pipe wall thickness is

Yuki888 [10]

Answer:

1113kN

Explanation:

The ouside diameter OD of the pipe is 61cm and the thickness T is 0.9cm, so the inside diameter ID will be:

Inside Diameter = Outside Diameter - Thickness

Inside Diameter = 61cm - 0.9cm = 60.1cm

Converting this diameter to meters, we have:

$60.1cm*\frac{1m}{100cm}=0.601m$

This inside diameter is useful to calculate the volume V of water inside the pipe, that is the volume of a cylinder:

$V_{water}=\pi r^{2}h$

$V_{water}=\pi (\frac{0.601m}{2})^{2}*120m$

$V_{water}=113.28m^{3}$

The problem gives you the water density d as 1.0kg/L, but we need to convert it to proper units, so:

$d_{water}=1.0\frac{Kg}{L}*\frac{1L}{1000cm^{3}}*(\frac{100cm}{1m})^{3}$

$d_{water}=1000\frac{Kg}{m^{3}}$

Now, water density is given by the equation $d=\frac{m}{V}$ , where m is the water mass and V is the water volume. Solving the equation for water mass and replacing the values we have:

$m_{water}=d_{water}.V_{water}$

$m_{water}=1000\frac{Kg}{mx^{3}}*113.28m^{3}$

$m_{water}=113280Kg$

With the water mass we can find the weight of water:

$w_{water}=m_{water} *g$

$w_{water}=113280kg*9.8\frac{m}{s^{2}}$

$w_{water}=1110144N$

Finally we find the total weight add up the weight of the water and the weight of the pipe,so:

$w_{total}=w_{water}+w_{pipe}$

$w_{total}=1110144N+2500N$

$w_{total}=1112644N$

Converting this total weight to kN, we have:

$1112644N*\frac{0.001kN}{1N}=1113kN$

7 0

3 years ago

An Otto cycle engine is analyzed using the cold air standard method. Given the conditions at state 1, compression ratio (r), and

lilavasa [31]

Answer:

Explanation:

The detailed and careful step by step calculation and analysis is as shown with appropriate formula in the attached files

4 0

3 years ago

Technician A says that burning of fossil fuels has increased the greenhouse gas CO 2 in the atmosphere. Technician B says that i

olchik [2.2K]

Answer:

Technician A

Explanation:

Why do I think technician A is correct it's because burning fossil fuel and then comes the greenhouse effect and the airborne particles get suspended in the air for a month or less but greenhouse gasses that cause warming for a very long time and this goes on and on weakening the ozone layer. I could go on and on but I don't feel like writing a book rn

3 0

2 years ago