Sun Sail
August 9th 2010 Posted at Patio Furniture
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Sun Sail
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 18 Square Heavy Duty Sun Shade Sail New Green Canopy  US $59.95
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 New Square 12 Sun Shade Sail Canopy Sand color Yard US $30.12
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 18x18 Square Sun Shade Sail Canopy Patio Outdoor Green Cover US $47.95
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 18 FT SQUARE SUN SHADE SAIL CANOPY HEAVY DUTY SAND US $65.90
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 New 24 FT Square Sun Sail Shade Canopy Outdoor Patio Garden Sand US $126.00
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 New Triangle Sun Shade Sail 165 Desert Sand Color US $25.99
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 Sun Shade Sail 12 x 12 Square Shading Canopy Sand US $47.95
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 New 115 Square Sun Shade Sail Desert Sand Color Kit US $43.69
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 New Square Rectangle Sun Shade Sails all Sizes US $54.99
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 NEW SUN SHADE SAIL 13x13 FT 4x4m SQUARE CANOPY GREEN US $54.95
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 New 10 Square Sun Shade Sail Yellow Rectangle Canopy US $39.99
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 New Sun Shade Sail 13 Square Shading Canopy Beige Sand US $54.95
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 New Sun Shade Sail 165 Triangle Shading Canopy Green US $44.95
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 10 Triangle Sun Shade Sail Sails Blue New Outdoor US $27.99
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 New Sun Shade Sail 12 Square Shading Canopy Green US $47.95
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 New 24 FT Square Sun Sail Shade Canopy Outdoor Patio Garden Green US $126.00
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 New 20×16 FT Rectangle Sun Sail Shade Canopy Outdoor Patio Garden Green US $78.99
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Ann Clark Sailboat Cookie Cutter $5.31 Tin cookie cutter in the shape of a SAILBOAT with sturdy tin handle and colorful recipe card. Each card includes a recipe for cookies and frosting. Size 4" H... |
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Egypt/creation Photo Mugs Between the sustaining Earth and the life-giving Sky, the Vessel of Life sails down the Nile, warmed by the Sun... .... |
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Medal commemorating the invasion of Prussia by Sweden; obverse Photo Mugs Medal commemorating the invasion of Prussia by Sweden. Obverse A three-masted ship under sail in fair weather, the sun above. Reverse A three-masted ship before the wind in bad weather, sails furled, and clouds above. A satirical medal referring to invasion of Prussia by Sweden..... |
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Scarface (1983) $2.99 ... |
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Scarface (1983) $9.99 ... |
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Black Sails In The Sunset $8.03 1999 release on Nitro for this raw and powerful East Bay hardcore punk band. 12 tracks including 'Strength Through Wounding', 'Exsanguination', 'Clove Smoke Catharsis', 'God Called In Sick Today' and more.... |
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Sailor Moon - The Legend Begins (TV Show, Vol. 1) [VHS] $12.98 High-pitched, relentlessly fast paced, and filmed in eye-gouging gumball colors, this video series combines two previously released dubbed episodes from the Japanese animated series, along with a couple of new ones. The adventures of a group of schoolgirl superheroes, Sailor Moon is a lighthearted kiddy variation on a ubiquitous Japanese subgenre, stories of alienated adolescents granted paranorma... |
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And the Ship Sails On [VHS] $13.99 Federico Fellini's 1984 And the Ship Sails On is one of the late master's most fanciful projects, while simultaneously striking one of the most somber notes in the director's filmography. The year is 1914, the eve of World War I and the coming destruction of Europe's old, cultured aristocracy, an elite class mourned in many a film from Renoir's The Grand Illusion to Truffaut's The Green Room.... |
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Easy Gardener Sun Sail-Triangle Easy gardener sun sails are ready-made to create instant cooling shade. Visually appealing, these pre-fabricated square and triangle shapes are made from high-quality easy gardener sun screen fabric, which allows refreshing breezes to flow through, doubling the sail's cooling power. Sails can be easily hung with minimum effort or tools over patio, driveways and other outdoor spaces to provide imme... |
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Heavy Duty Premium Tarp ... |
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1 L SHAPE THRU FITTING $6.00 SIDE PANEL ACCESSORY FITTING... |
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National Lampoon'S Dorm Daze 2 $2.99 ... |
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suki suki intensive nourishing cream 1 fl oz - 1 fl oz $53.87 There is light at the end of the tunnel. Brighten and lighten your dull skin with a multi-symptom product designed to plump, firm, tone, brighten, and even your complexion while hydrating your skin. suki intensive nourishing cream with brightening complex fights off environmental stressors as it heals sun damage, inhibits melanin production, and stimulates collagen production....... |
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Watermans Applied Science Sunscreen Sun Screen Sun Cream Two Skin Tones Sports long lasting, sunblock, sweat proof, very sweat resistant, very water resistant, water proof, surf, surfing, scuba dive, swimming A non-greasy, lightweight, very water resistant, very sweat resistant, broad-spectrum protectant infused for your face and hands. The Face Stick Sunscreen is a hands-free, one touch, way to protect your face and hands without the mess of traditional tubes and bottles. Titanium dioxide provides proven UVA and UVB protection. Apply wet or dry. Watermans special formula ensures it will be there for y... |
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Columbia Men's Super Tamiami Long Sleeve Shirt (Small, Beacon/4 Color Check) $75.00 When you can't take much because the sea kayak, or bush plane has limited cargo capacity, make sure you toss in at least one Men's Columbia Super Tamiami Long Sleeve Shirt. The reason? An exceptional antimicrobial treatment that will keep you fresh and odor free for multiple wearings. We all know a 7 day trip doesn't require 14 shirts, or even 7, and now it will require even less. The yarn dyed pr... |
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Columbia Sportswear Super Bahama Short Sleeve Shirt $60.00 As the sun eases into the western sky, and you want a little color on your arms, pull on the Men's Columbia Super Bahama Short Sleeve Shirt. This popular button-up receives new fun prints and super soft Tactel nylon for 2012, while retaining the Omni-Shade UPF 30 sun protection rating. By using a tighter weave, UV reflectors and UV absorbing technology you receive unrivaled solar protection in a l... |
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Columbia Sportswear Super Bahama Multi Large Plaid Long Sleeve Shirt $65.00 Whether you're casting with an SA Ultra Bonefish taper, or just your best pickup line, be the epitome of casual comfort in your Men's Columbia Super Bahama Long Sleeve Shirt. Columbia's popular shirt gets an upgrade for 2012 with fun versatile prints and soft Tactel nylon. Lightweight and quick drying, this button-up features Omni-Shade's tight weave, UV reflectors and UV absorption technology for... |
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24/pk Watercraft Shaped Silicone Rubber Bands Bracelets $1.40 Watercraft Shaped Rubber Bands Bracelets Quantity of ONE pack is 24 shapes. Contains 4 each of 6 shapes: Speed boat, Bass Boat, Sail Boat, Pontoon Boat, Yacht, Jet Ski Collect 'em Wear 'em Trade 'em What fun! Bring the fun back into your home or office with these clever shaped rubber bands! They look and behave like normal (albeit colorful) rubber bands when stretched. But when remo... |
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Dual Sails Pirate Ship Play Set ... |
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Dual Sail Pirate Ship Imaginative small fry will enjoy exciting adventures galore with our wonderful pirate ship play set. It’s the most comprehensive and creative set we’ve seen. Rolls along with free wheel wave action that turns any smooth floor into the high seas. Has a crow’s nest for spotting treasure-laden vessels and a dinghy for rowing ashore. The six action figures are... |
What is the max total momentum/sqm that a solar sailed spaceship can gather from the sun?
When I say 'total' I mean in the course of its full journey, from somewhere close to the sun to very far away from it. So that relates to its final speed, the one at which it will be eventually cruising away.
Of course, a crucial detail to work out in the first place is how close to the sun it can safely go before unfurling its sails.
Interesting question. To make the math easy, let's assume a 1-kg spacecraft with a 1-m^2 area. We will also treat the Sun as a point source.
The light pressure from the Sun on a blackbody is 4.5698281*10^-6 Pascals at a distance of 1 AU. Giving the light pressure in Pascals as a function of distance from the Sun in meters, we get:
pressure = 1.02271 * 10^17 / R^2
where R is the distance in meters.
Since our spacecraft has 1 m^2 of area, 1 Pascal of pressure yields 1 Newton of force. But wait! That was for a blackbody (a perfect absorber of light). If our spacecraft instead is a perfect reflector, we can double our thrust, because the photons are reflected, giving them twice the change in momentum, and thus giving our spacecraft twice the change in momentum (and therefore twice the force). So, in fact, our ultra-shiny spacecraft feels 2 Newtons of force at 1 Pascal of ambient light pressure.
The amount of work done on the solar sail is the integral of force times distance. This must also be the final kinetic energy of the spacecraft. Therefore, we have:
KE = integral( (1 m^2)*(1.02271 * 10^17 / R^2), [R, R0, R1])
That's the integral of (area * pressure) with respect to R, from R0 (initial distance to the Sun) to R1 (final distance to the Sun).
Let's assume we start at a distance of 0.1 AU (1.49598 * 10^10 meters), and fly off to infinity. Integrating, we get:
KE = integral( (1 m^2)*(1.02271 * 10^17 / R^2), [R, R0, R1])
KE = (1.02271 * 10^17) * (1/R1 - 1/R2)
KE = (1.02271 * 10^17) * (1/(1.49598 * 10^10) - 1/∞)
KE = (1.02271 * 10^17) * (1/(1.49598 * 10^10) - 0)
KE = (1.02271 * 10^17) * (1/(1.49598 * 10^10))
KE = 6.83639 * 10^6 (Joules)
Momentum (p) is related to kinetic energy by
KE = p^2 / (2*m)
therefore
p = sqrt(2*m*KE)
p = sqrt(2 * (1 kg) * (6.83639 * 10^6 Joules))
p = 3,697.67 kg*m/s
Now, this ignores gravity, which we will be fighting against the whole trip. But if we assume the spacecraft has a negligible mass compared to the size of its sail, then we can essentially ignore gravity. This number therefore gives us a theoretical maximum momentum that a solar sail could achieve, starting from 0.1 AU traveling out to infinity
Sun Sail
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