This project must be done by individuals.

Joe Aerospace decides to make a "solar sail" for his private spaceship. The "sail" uses radiation pressure from the Sun to move a ship, in the same way that a regular sail uses pressure from the wind. Joe uses ordinary aluminum foil (Reynolds Wrap or the equivalent) for his sail.

- What is the mass per square meter of aluminum foil?
The Sun radiates a great deal of energy per second; see Appendix C for its power. Assume that all of this energy is emitted as photons of wavelengths 550 nanometers -- greenish-yellow light. These photons each have

energy E = 3.61 x 10^(-19) Joules momentum p = 1.21 x 10^(-27) kg*m/s

- How many photons of this sort does the Sun emit each second?
Joe's sail is a square, 100 meters on a side, located at the Earth's distance from the Sun. He orients it so that photons strike it face-on and bounce back towards the Sun.

- How many photons strike Joe's sail each second?
- If the photons are reflected perfectly back towards the Sun,
how much momentum does a single photon transfer to the sail?
- How much momentum is transferred to the sail each second?
- Use impulse to calculate the force exerted on the
sail by the photons.
- Calculate the force of gravity due to the Sun on the sail.
- What is the net acceleration of Joe's sail?

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This page maintained by Michael Richmond.
Last modified Nov 1, 2004.
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Copyright © Michael Richmond. This work is licensed under a Creative Commons License.