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shtirl [24]
3 years ago
14

How Does A Shoe Box Solar Cooker Work?

Engineering
1 answer:
Natalija [7]3 years ago
4 0

Answer:

the sun gives off light while at the same time gives off heat. the shoe box cooker takes that heat and light and reflects it around the shoe box. then the heat settles down into whatever is in the shoe box. the heat after being reflected around the shoe box is magnified by the foil wrapped in the box thus allowing the food or drink to be heated. the foil is a conductor of heat because it is metal .

Explanation:

hope this helps!

You might be interested in
The denominator of a fraction is 4 more than the numenator. If 4 is added to the numenator and 7 is added to the denominator, th
kati45 [8]

Answer:

\frac{3}{7}

Explanation:

Lets take the numerator of the fraction to be = x

So the denominator of the fraction is 4 more than the numerator = x+4

The fraction is ;\frac{x}{4+x}

Now add 4 to the numerator and add 7 to the denominator as;

\frac{x+4}{4+x+7} =\frac{x+4}{x+11}

This new fraction is equal to 1 half =1/2

write the equation as;

\frac{x+4}{x+11} =\frac{1}{2}

perform cross-product

2(x+4 )=1( x+11 )

2x+8 = x + 11

2x-x = 11-8

x=3

The original fraction is;  

\frac{x}{4+x} =\frac{3}{3+4} =\frac{3}{7}

3 0
3 years ago
The water in a large lake is to be used to generate electricity by the installation of a hydraulic turbine-generator at a locati
Lynna [10]

Answer:

a) 0.76

b) 0.80

c) 1964 kW

Explanation:

GIVEN DATA:

\dot m = 5000 kg/s

Assume Mechanical energy at exist is negligible

A) Take lake bottom as reference, and then kinetic and potential energy  are taken as zero.

change in mechanical energy is givrn as

e_{in} - e_{out} = \frac{P}{\rho} - 0 = gh = 9.81 \times 50( \frac{1 kJ/kg}{1000 m^2/s^2}

                         = 0.491 kJ/kg

\Delta \dot E_{mec} = \dot m (e_{in} - e_{out}) = 5000 \times 0.491 = 2455 kW

\eta_{OVERALL}  = \frac{\dot W}{\Delta \dot E_{mec}} = \frac{1862}{2455} = 0.76

B) \eta -{gen} = \frac{\eta_{overall}}{\eta_{gen}} = \frac{0.76}{0.95} = 0.80

c) \dot W_{shaft} = \eta_{overall} \left | \Delta \dot E_{mec} \right | = 0.80(2455)

\dot W_{shaft} = 1964 kW

7 0
4 years ago
As the driver of the red SUV, what are your options for navigating this roundabout?
IgorC [24]

Your options for navigating this roundabout would include driving in a counter-clockwise direction and then making your exit to the right lane.

<h3>What is a roundabout? </h3>

A roundabout is a circular intersection that make junctions or intersections of roads safer, because it is designed and developed to physically direct drivers and pedestrians to move in a counter-clockwise direction.

In this scenario, your options for navigating this roundabout as the driver of the red SUV would include driving in a counter-clockwise direction and then making your exit to the right lane.

Read more on roundabout here: brainly.com/question/22580476

#SPJ1

3 0
2 years ago
The fins attached to a surface are determined to have an effectiveness of 0.9. Do the rate of heat transfer from the surface dec
Nesterboy [21]

Answer: The rate of heat transfer decreases.

Explanation:

Fin effectiveness is defined as the ratio of heat transfer rate from a  finned surface to the heat transfer rate from the same surface if there were no fins.  Its  value is expected to be greater than 1.

Having effectiveness  value of 0.9  which is less than 1 indicates that the heat transfer rate will decrease since a fin effectiveness smaller than 1 shows that the  fin acts as insulation (thermal insulation).

8 0
3 years ago
Design a 7.5-V zener regulator circuit using a 7.5-V zener specified at 10mA. The zener has an incremental resistance of rZ = 30
hram777 [196]

Answer:

The answer is given in the explanation.

Explanation:

The circuit is as indicated in the attached figure.

From the analytical description the zener voltage is given as

V_z=V_z_o+I_zr_z

Here

Vzo is the voltage at which the slope of 1/rz intersects the voltage axis it is equal to knee voltage.

The equivalent model is shown in the attached figure.

From the above equation, Vzo is calculated as

V_z_o=V_z-I_zr_z

Here Vz is given as 7.5 V

Iz is given as 10 mA

rz is given as 30 Ω

Thus the Vzo is given as

V_z_o=V_z-I_zr_z\\V_z_o=7.4-30*10*10^{-3}\\V_z_o=7.5-0.3\\V_z_o=7.2 V

The value of I_L is given as 5 mA

Now the expression of current is as

I=I_z+I_L\\I=10mA+5mA\\I=15 mA

Now the resistance is calculated as

R=\dfrac{V-Vo}{I}\\R=\dfrac{10-7.2}{15*10^{-3}}\\R=186.66

So the value of resistance is 186.66 Ω.

Considering the supply voltage is increased by 10%

V is 10-10%*10=10+1=11 so the

R=\dfrac{V-Vo}{I}\\186.66=\dfrac{11-V_o}{15*10^{-3}}\\V_o=8.2 V

Considering the supply voltage is decreased by 10%

V is 10-10%*10=10-1=9 so the

R=\dfrac{V-Vo}{I}\\186.66=\dfrac{9-V_o}{15*10^{-3}}\\V_o=6.2 V

Now if the supply voltage is 10% high and the value of Load is removed i.e I=Iz only which is 10mA

so

R=\dfrac{V-Vo}{I'}\\186.66=\dfrac{11-V_o}{10*10^{-3}}\\V_o=9.13 V

Now the largest load current thus that the supply voltage is 10% low and the current of zener is knee current thus

V_z_o=V_z-I_zr_z\\V_z_o=7.5-30*0.5*10^{-3}\\V_z_o=7.5-0.015\\V_z_o=7.485 V

R=\dfrac{V-Vo}{I'}\\186.66=\dfrac{9-7.485}{I}\\I=10.71 mA

The load voltage is 7.485 V

8 0
3 years ago
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