Math Is Fun Forum

nervousnellu

Member

Registered: 2008-03-23

Posts: 2

trig

I'm making a solar funnel, and I'd like to calculate the angle of the funnel given width and height so the rays hitting the very top of the funnel just make it in the box, they don't hit the reflector on the other side. A diagram might make it clearer.

That's a cross section of the funnel and box. So what's the smallest angle (which makes the largest funnel) where the sun hitting the very top of the funnel goes in the box? assume the funnel and box are lined up perfectly with the sun, and all the light is parallel.

Does that make sense? can I make it any clearer?

luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: trig

i.e. you get triangle on right, in which the right angle is enforced, and we need to find the value of theta.

Atleast i think that should be right, but i dont have to time to try and work out theta

Last edited by luca-deltodesco (2008-03-23 23:15:53)

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nervousnellu

Member

Registered: 2008-03-23

Posts: 2

Re: trig

That really helps, thanks. nice diagram, too

I'll look at it again in the morning, it's getting too late to drag out the old textbooks.

nervousnellu

Member

Registered: 2008-03-23

Posts: 2

Re: trig

so close, yet so far. anyone want to throw a dog a bone?