What is the solar constant in certain area of earth per day?

[viniterranova]

Homework Statement

The solar constant, the amount of solar energy reaching the Earth per unit time and area above the atmosphere and an
element of area perpendicular to the direction from sunlight is 1.36 kW / m². For an element of area whose normal
makes a angle q with the direction of the solar rays, the energy flow varies with cos theta.
a) Calculate the total amount of solar energy reaching the Earth per day.


Solar Constat I=1.36 kW/m^2

Homework Equations

Q=C*m*ΔT

The Attempt at a Solution

From the equation above I wrote,
Q=Δt*C*S*cos Θ

Intregrating, taking a small infinitesimal.

dQ=C*Δt*dS*cos Θ

Q=C*Δt∫cos Θ*dS.

 

[mfb]

This is just geometry, you don't have to integrate anything (you can, but it just makes the problem more complicated). As seen from the sun, how does the Earth look like?

 

[viniterranova]

Someone said that I should integrate it. So, if not for me the Earth is like a ideal point.

 

[dauto]

Someone said that I should integrate it. So, if not for me the Earth is like a ideal point.

No, not a point. A point is too small to represent the view of the Earth. Look at a picture of the Earth what does it look like? By the way, the formula you provided in the "Relevant equations" section is completely irrelevant. One more thing, that should've been posted in the "Introductory Physics Homework" forum.

 

[viniterranova]

So, what is the way to solve the problem?

 

[mfb]

See post #2:

As seen from the sun, how does the Earth look like?

Certainly not like a single point!

 

[dauto]

So, what is the way to solve the problem?

One step at a time. Before solving the problem you have to first understand the problem. Let put if a different way. The amount of light collected by the Earth depends on how large a target the Earth is. That's why we asked what the Earth looks like from the point of view of the sun to which you responded "a point", but that makes no sense so you should try again instead of just ask "So, what is the way to solve the problem?" You're supposed to show some effort.

 

[viniterranova]

In this case, I think the earth´s half circunference x one meter.

 

[mfb]

Why one meter?
What's the relevance of "1 meter" for the shape of earth?

If you look at the moon, how does it look like? Can you describe the shape?

 

[dauto]

In this case, I think the earth´s half circunference x one meter.

That doesn't mean anything. It's not even wrong. It's just meaningless