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The intensity of the Sun's light in the ...

The intensity of the Sun's light in the vicinity of the earth is about `1000 W//m^2` .Imagine a spacecraft with a mirrored square sail of dimension 1.0 km. Estimate how much thrust (in newtons) this crafts will experience due to collisions with the Sun's photons

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The correct Answer is:
7 N
Assume of photons bounce off the sail with no change in the magnitude of their momentum .
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  1. The intensity of the Sun's light in the vicinity of the earth is about...

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